Mu (Miscellaneous Utilities)
1 Introduction
1.1 Terms and Notation Used in this Manual
1.2 Using Mu in Your Program
1.3 Reporting Bugs
2 Parsing Options and Environment
2.1 Option Structure
2.2 Aliases for Options and Environment Variables
2.3 Negatable Options
2.3.1 Negation Prefixes
2.4 Option Arguments
2.4.1 Option Argument Types
2.5 Option Callbacks
2.6 Parsing Enumerated Arguments to Options
2.7 Parsing Suboptions
2.8 Parsing the Environment
2.9 Option Parsing Flags
2.10 Ordered Option Parsing
2.11 Formatting Help
2.12 Option Parsing Errors
3 Formatting Text
3.1 Controlling Formatted Output
3.2 Formatting Example
4 Safety Functions
5 Compatibility Functions
Appendix A GNU General Public License
Appendix B GNU Free Documentation License
Appendix C Concept Index
Appendix D Function and Macro Index
Appendix E Type Index
Appendix F Variable and Constant Index
Mu (Miscellaneous Utilities)
****************************
This is the manual for Mu (Miscellaneous Utilities) version 0.0, last
updated 7 February 2024.
Copyright © 2020 Asher Gordon <AsDaGo@posteo.net>
You may copy, modify, and redistribute this manual under the terms
of the GNU General Public License version 3 (or, at your option,
any later version), and/or the GNU Free Documentation License,
Version 1.3 (or, at your option, any later version).
This manual is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published
by the Free Software Foundation, either version 3 of the License,
or (at your option) any later version.
This manual is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. *Note GNU
General Public License:: for more details.
You should have received a copy of the GNU General Public License
along with this manual. If not, see
<https://www.gnu.org/licenses/>.
Permission is granted to copy, distribute and/or modify this
document under the terms of the GNU Free Documentation License,
Version 1.3 or any later version published by the Free Software
Foundation; with no Invariant Sections, no Front-Cover Texts, and
no Back-Cover Texts. A copy of the license is included in the
section entitled "GNU Free Documentation License" (*note GNU Free
Documentation License::).
1 Introduction
**************
Mu is a general purpose convenience library. It provides functions
which perform common tasks, as well as some compatibility functions.
All code examples in this manual that can be compiled on their own
are available in the ‘doc/examples’ directory in the source
distribution.
1.1 Terms and Notation Used in this Manual
==========================================
There are several types of arguments dealt with in this manual:
arguments to command line options; non-option, positional arguments
passed on the command line; and parameters passed to functions. When we
refer to arguments passed to command line options, we will use the term
“argument†on its own. When we refer to non-option, positional
arguments passed on the command line, we will use the term “positional
argumentâ€. When we refer to the value of an environment variable, we
will use the term “valueâ€. When we refer to parameters passed to
functions, we will use the term “parameterâ€.
When referring to a field in a C ‘struct’ or ‘union’, we will use the
term “fieldâ€.
In examples, messages printed to standard output will be prefixed
with "⊣", while messages printed to standard error will be prefixed with
"error→".
1.2 Using Mu in Your Program
============================
Mu is written in C, and currently no bindings exist for other languages.
So (for now at least) you can only use Mu in C programs.
Several header files are provided by Mu. Each one provides a
different category of functions. All header files are installed in the
‘mu’ subdirectory. So to include, for example, ‘compat.h’, write
‘#include <mu/compat.h>’.
To link with the library, use ‘-lmu’ as an argument to the linker.
Note: Since Mu is released under the terms of the GNU General Public
License, you may not use it in proprietary programs. If your program
links with Mu, it must be licensed under the GNU GPL or a compatible
license. Please see *note GNU General Public License:: for more
details.
Please note: Mu is not currently stable, and the API is subject to
change. Feel free to use Mu, but please keep this in mind.
1.3 Reporting Bugs
==================
Please report bugs to the bug tracker at Savannah
(https://savannah.nongnu.org/bugs/?group=libmu&func=additem). You may
also email bug reports to the <libmu-bug@nongnu.org> mailing list. See
also the list information page for libmu-bug
(https://lists.nongnu.org/mailman/listinfo/libmu-bug). Include enough
information to reproduce the bug if possible, as well as the version of
Mu, your machine architecture, operating system, etc. Make sure to read
the documentation for the functions you are using, and ensure that you
are using the functions correctly. You should also include any error
messages if applicable, and a backtrace if you can. If possible,
include a source file (preferably minimal) that causes the bug to occur.
If you are reporting a test failure (run by ‘make check’), include
the file ‘tests/testsuite.log’ in your report. Even if you're not
reporting a test failure, it can still be helpful to run ‘make check’
and include ‘tests/testsuite.log’.
For more information on writing effective bug reports, I suggest
reading Simon Tatham's excellent essay, ‘How to Report Bugs Effectively’
(https://www.chiark.greenend.org.uk/~sgtatham/bugs.html)
You can also send reports for bugs in this manual itself to the bug
tracker (https://savannah.nongnu.org/bugs/?group=libmu&func=additem) or
mailing list <libmu-bug@nongnu.org>.
2 Parsing Options and Environment
*********************************
Mu includes option parsing capability. Mu can parse command line
options; both short options (a single dash followed by a letter, e.g.,
‘-s’) and long options (two dashes followed by a multi-letter word,
e.g., ‘--long’). Long options may also be specified with a single ‘-’
as long as the flag ‘MU_OPT_BUNDLE’ is not set (*note Option Parsing
Flags::).
Mu also supports parsing the environment. *Note Parsing the
Environment:: for more information.
The option structure is fairly complicated, and its organization is
subject to change. For that reason, it is highly recommended that you
use designated structure initializers or set the values after
declaration.
You can use designated initializers like this:
const MU_OPT options[] = {
{
.short_opt = "s",
.long_opt = "long",
.has_arg = MU_OPT_NONE
},
{ 0 }
};
However, since designated initializers are only available in C99 and
later (*note (gcc)Designated Inits::), this may not be an option for
you. The following is equivalent to the above example without using
designated initializers:
const MU_OPT options[2] = { 0 };
options[0].short_opt = "s";
options[0].long_opt = "long";
options[0].has_arg = MU_OPT_NONE;
If you would like to use option parsing features, include
‘mu/options.h’.
-- Data Type: MU_OPT_CONTEXT
This is an opaque context for parsing options. It is allocated
using ‘mu_opt_context_new’ and similar functions. To free it, you
must use ‘mu_opt_context_free’. Both functions (among others) are
described below.
-- Function: MU_OPT_CONTEXT * mu_opt_context_new (int ARGC, char
**ARGV, const MU_OPT *OPTIONS, int FLAGS)
-- Function: MU_OPT_CONTEXT * mu_opt_context_new_with_env (int ARGC,
char **ARGV, char **ENVIRONMENT, const MU_OPT *OPTIONS, int
FLAGS)
Allocate and return a new option parsing context. ARGV is the list
of arguments to be parsed. ‘ARGV[0]’ should be the name the
program was invoked as, and the rest of ARGV should be the
arguments given on the command line. ARGC is the length of ARGV.
Normally, ARGC and ARGV should be used directly from ‘main’.
The returned context can also be used for parsing environment
variables through the ‘env_var’ field of the option structure
(*note Option Structure::). When ‘mu_opt_context_new’ is used to
allocate the option parsing context, environment variables are
parsed in the program environment (*note (libc)Environment
Access::). If you want to use an alternative environment, use
‘mu_opt_context_new_with_env’ to allocate the option parsing
context, in which case environment variables will be parsed in
ENVIRONMENT. ENVIRONMENT can also be ‘NULL’, in which case
environment variable parsing will be disabled. ENVIRONMENT (or the
program environment in the case of ‘mu_opt_context_new’) is never
modified, unless, of course, any of the callbacks modify it (*note
Option Callbacks::).
Normally, all arguments will be parsed at once when ‘mu_parse_opts’
is called, and the context returned by these functions should only
be passed to ‘mu_parse_opts’ once. However, you can use
‘mu_opt_context_set_arg_callback’ or the ‘MU_OPT_CONTINUE’ flag if
you care about the order in which options and arguments appear on
the command line (*note Ordered Option Parsing::).
OPTIONS is the list of options and environment variables that can
occur in ARGV and ENVIRONMENT (or the program environment). *Note
Option Structure::. Note that OPTIONS is copied into the returned
context, not used directly. Because of this, you need not worry
about OPTIONS going out of scope. For example, you might write a
function which returns an option parsing context from a list of
options which is local to that function's scope. Of course, you
still need to ensure that no pointers referenced by any of the
fields in OPTIONS go out of scope (‘cb_data’ for example; *note
Option Structure::).
FLAGS is a bitmask of flags that effect how options are parsed
(*note Option Parsing Flags::).
If you want to write a function which parses some options, but then
leaves the rest for the caller to parse, consider using the
‘MU_OPT_ALLOW_INVALID’ flag (*note Option Parsing Flags::). Note,
however, that it may instead be better to use
‘mu_opt_context_add_options’ (see below).
On error, this function returns ‘NULL’ and the external variable
‘errno’ will be set to indicate the error. For a function which
terminates the program on error, use ‘mu_opt_context_xnew’ and
‘mu_opt_context_xnew_with_env’ (*note Safety Functions::).
-- Function: int mu_opt_context_free (MU_OPT_CONTEXT *CONTEXT)
Free the option context, CONTEXT. For the ‘cb_data’ fields in each
option, the ‘cb_data_destructor’ field (if any) will be used to
free that data (*note Option Structure:: and *note Option
Callbacks::). If any of the destructors return nonzero,
‘mu_opt_context_free’ will return nonzero as well. Otherwise,
‘mu_opt_context_free’ will return zero.
Note that _all_ the destructors are called, even if one or more of
them return nonzero.
-- Function: int mu_parse_opts (MU_OPT_CONTEXT *CONTEXT)
Parse the options given in CONTEXT. Use ‘mu_opt_context_new’ or
‘mu_opt_context_new_with_env’ (see above) to create the context.
On success, the number of arguments parsed is returned. You can
pass this value to ‘mu_shift_args’ (see below). On error, an error
code is returned, which can be detected by ‘MU_OPT_ERR’ (*note
Option Parsing Errors::).
Note that if ‘mu_opt_context_set_arg_callback’ was called on
CONTEXT, the number of _positional_ arguments will be included in
the return value as well, if neither the ‘MU_OPT_PERMUTE’ nor
‘MU_OPT_STOP_AT_ARG’ flags are used. However, if either of these
flags are used, the return value will _not_ include the number of
positional arguments parsed, even if
‘mu_opt_context_set_arg_callback’ was called. This is so that you
can shift the arguments by the return value and the remaining
arguments will be the non-option positional arguments. Note that
this would not be useful if neither the ‘MU_OPT_PERMUTE’ flag nor
the ‘MU_OPT_STOP_AT_ARG’ flag was passed, because it would not be
guaranteed that all the arguments left after shifting actually
_were_ the non-option positional arguments. For this reason,
positional arguments are included in the return value when neither
of these flags are passed. *Note Ordered Option Parsing::.
-- Enumerated Type: enum MU_OPT_WHERE
This type specifies whether to append or prepend options (see
‘mu_opt_context_add_options’ below). Values of this type can be
either of the following:
‘MU_OPT_PREPEND’
Indicate that options should be prepended (before existing
options).
‘MU_OPT_APPEND’
Indicate that options should be appended (after existing
options).
-- Function: int mu_opt_context_add_options (MU_OPT_CONTEXT *CONTEXT,
const MU_OPT *OPTIONS, enum MU_OPT_WHERE WHERE)
Add OPTIONS to CONTEXT. If WHERE is ‘MU_OPT_APPEND’, append
OPTIONS to the current options in CONTEXT. Otherwise, if WHERE is
‘MU_OPT_PREPEND’, prepend OPTIONS instead. If WHERE is neither
‘MU_OPT_APPEND’ nor ‘MU_OPT_PREPEND’, ‘mu_opt_context_add_options’
will return nonzero and ‘errno’ will be set to ‘EINVAL’.
On success, this function returns zero. On error, this function
returns nonzero and sets ‘errno’ to indicate the error.
If you want to add options for printing usage information, use
‘mu_opt_context_add_help_options’ (*note Formatting Help::).
-- Function: void mu_shift_args (int *P_ARGC, char ***P_ARGV, int
AMOUNT)
This function shifts the arguments in ‘*P_ARGV’ by AMOUNT and
subtracts AMOUNT from ‘*P_ARGC’. The old ‘(*P_ARGV)[0]’ will be
copied to the new ‘(*P_ARGV)[0]’ after the shift is performed. It
can be useful to call this function with the return value of
‘mu_parse_opts’ passed as AMOUNT(1) and P_ARGC and P_ARGV as the
addresses of ARGC and ARGV respectively, as passed to
‘mu_opt_context_new’.
---------- Footnotes ----------
(1) But first you should make sure the return value is not an error
code (*note Option Parsing Errors::).
2.1 Option Structure
====================
-- Data Type: MU_OPT
This structure specifies a single option, the arguments the option
takes, and the actions to perform when the option is found. If all
fields are ‘0’, that will indicate that this is the end of the
options list.
Unless otherwise specified, these fields may be used both in
regular options and suboptions. If an option takes suboptions as
arguments, there are some fields which it may not use. Likewise,
if an option _does not_ take suboptions as arguments, there are a
few fields which _it_ may not use. See below for details. *Note
Parsing Suboptions:: for more information on suboptions.
‘const char *category’
This field, if used, is a category for the options following
the one in which this field appears. It has no effect on
option parsing, only on help and man output (*note Formatting
Help::). This field may not contain newlines (‘\n’).
If this field is the empty string, the following options will
be separated by a newline in help output, and it will have no
effect in man page output.
If this field is used, it must be the only field used. You
may not set any other fields if this field is set.
For an example of how this field is used, see *note Formatting
Help::.
‘const char *short_opt’
This is the short option character if any, possibly including
aliases, or ‘NULL’ if this option does not have a short option
equivalent.
You may specify multiple aliases by simply including more
characters in the ‘short_opt’ (*note Option Aliases::). Note
that if ‘short_opt’ is not ‘NULL’, it must be terminated by a
null byte.
This field must not be used in suboptions (*note Parsing
Suboptions::).
‘const char *long_opt’
This is the long option string (without leading dashes), or
‘NULL’ if this option does not have a short option equivalent.
‘long_opt’ must not contain the ‘=’ character, because that is
used for passing arguments.
You may specify aliases separated by ‘|’ (*note Option
Aliases::).
This field must not be used in suboptions (*note Parsing
Suboptions::).
When matching against ‘long_opt’, abbreviation is allowed as
long as it is unambiguous.
‘const char *subopt_name’
This is the name of the suboption. Like ‘long_opt’, it may
not contain the ‘=’ character. Also like ‘long_opt’, matching
allows abbreviation as long as it is not ambiguous.
You may specify aliases separated by ‘|’ (*note Option
Aliases::).
This field must only be used in suboptions (*note Parsing
Suboptions::).
‘const char *env_var’
This is the name of an environment variable. Environment
variables act exactly like options, except that they are
passed in the environment rather than on the command line.
Like ‘long_opt’, ‘env_var’ must not contain the ‘=’ character,
because that is used for indicating the value of an
environment variable.
Unlike ‘long_opt’ and ‘subopt_name’ (above), abbreviation is
*not* allowed.
You may specify aliases separated by ‘|’ (*note Option
Aliases::).
*Note Parsing the Environment:: for more information about
parsing the environment with ‘mu_parse_opts’ and *note
(libc)Environment Variables:: for more information on
environment variables in general.
‘enum MU_OPT_HAS_ARG has_arg’
This specifies whether the option takes an argument or not,
and whether the argument is optional or required if the option
does take an argument. ‘has_arg’ can have the value
‘MU_OPT_NONE’ if the option takes no argument,
‘MU_OPT_OPTIONAL’ if the option may optionally take an
argument, or ‘MU_OPT_REQUIRED’ if the option requires an
argument. *Note Option Arguments:: for more information on
how required and optional arguments are parsed and handled
differently.
‘enum MU_OPT_ARG_TYPE arg_type’
The type of the argument if ‘has_arg’ is not ‘MU_OPT_NONE’.
*Note Option Argument Types::.
‘int negatable’
If this is nonzero, the option may be negated. For short
options, this means using ‘+’ instead of ‘-’, and for long
options and suboptions, it means prefixing the option with
‘no-’ or the specified negation prefixes (*note Negation
Prefixes::). Environment variables may not be negated. *Note
Negatable Options:: for more details.
This field may only be used if ‘has_arg’ is ‘MU_OPT_NONE’.
‘int *found_opt’
If ‘found_opt’ is not ‘NULL’, ‘*found_opt’ will be set to ‘1’
if the option was found, or ‘0’ if the option was not found.
‘int *found_arg’
If ‘found_arg’ is not ‘NULL’, ‘*found_arg’ will be set to ‘1’
if an argument to the option was found, or ‘0’ if no argument
was found.
‘void *arg’
If ‘arg’ is not ‘NULL’, ‘*arg’ will be set to the argument if
an argument was found. To test if an argument was found, use
‘found_arg’. The type of the argument is determined by
‘arg_type’ (*note Option Argument Types::).
This field must only be used if ‘has_arg’ is not ‘MU_OPT_NONE’
and ‘arg_type’ is not ‘MU_OPT_SUBOPT’ (*note Option
Arguments:: and *note Parsing Suboptions::).
‘int bool_default’
‘long int_default’
‘double float_default’
‘const char *string_default’
‘FILE *file_default’
‘DIR *dir_default’
‘int enum_default’
The default values for ‘*arg’ (see above) if the option is not
found. ‘bool_default’ should be used for arguments of type
‘MU_OPT_BOOL’, ‘int_default’ should be used for arguments of
type ‘MU_OPT_INT’ and so on. *Note Option Argument Types::
for more information.
These fields may only be used if ‘has_arg’ is not
‘MU_OPT_NONE’.
‘const char **argstr’
If ‘argstr’ in not ‘NULL’, ‘*argstr’ will be set to the raw,
unprocessed argument unless otherwise specified in *note
Option Argument Types::. ‘*argstr’ is equal to ‘*arg’ if and
only if ‘arg_type’ is ‘MU_OPT_STRING’.
This field must only be used if ‘has_arg’ is not ‘MU_OPT_NONE’
and ‘arg_type’ is not ‘MU_OPT_SUBOPT’ (*note Option
Arguments:: and *note Parsing Suboptions::).
‘int (*callback_none) (void *, char *)’
‘int (*callback_negatable) (int, void *, char *)’
‘int (*callback_bool) (int, int, void *, char *)’
‘int (*callback_int) (int, long, void *, char *)’
‘int (*callback_float) (int, double, void *, char *)’
‘int (*callback_string) (int, const char *, void *, char *)’
‘int (*callback_file) (int, const char *, FILE *, void *, char *)’
‘int (*callback_directory) (int, const char *, DIR *, void *, char *)’
‘int (*callback_enum) (int, int, void *, char *)’
‘int (*callback_subopt) (int, void *, char *)’
If the corresponding callback for ‘arg_type’ is set (*note
Option Argument Types::), it will be called when the option is
found. *Note Option Callbacks:: for a description of the
arguments these callbacks take and their return values.
Note: only one of the callbacks may be set at a time.
‘callback_none’ may only be used if ‘has_arg’ is ‘MU_OPT_NONE’
and ‘negatable’ is zero. ‘callback_negatable’ may only be
used if ‘has_arg’ is ‘MU_OPT_NONE’ and ‘negatable’ is nonzero.
‘void *cb_data’
The DATA argument to pass to the above callbacks. *Note
Option Callbacks::.
This field must not be used if ‘arg_type’ is ‘MU_OPT_SUBOPT’
(*note Parsing Suboptions:: and *note Option Argument
Types::).
‘int (*cb_data_destructor) (void *DATA)’
If ‘cb_data’ contains dynamically allocated data or anything
else that needs to be released back to the system (e.g., file
descriptors), set ‘cb_data_destructor’ to a function which
will release all of that data, including ‘cb_data’ itself if
it was dynamically allocated as well. If an error occurred,
e.g., when closing a file descriptor, ‘cb_data_destructor’
should return nonzero.
As a simple example, if ‘cb_data’ was dynamically allocated
but does not contain dynamically allocated data, you can set
this to a function which will call ‘free(DATA)’ and return
‘0’.
This field must not be used if ‘arg_type’ is ‘MU_OPT_SUBOPT’
(*note Parsing Suboptions:: and *note Option Argument
Types::).
‘long ibound.lower’
‘long ibound.upper’
Lower and upper bounds (inclusive) for integer arguments. If
you don't want any bounds, set ‘ibound.lower’ to ‘LONG_MIN’
and ‘ibound.upper’ to ‘LONG_MAX’.
These fields must only be used if ‘arg_type’ is ‘MU_OPT_INT’
(*note Option Argument Types::).
‘double fbound.lower’
‘double fbound.upper’
Lower and upper bounds (inclusive) for floating point
arguments. If you don't want any bounds, set ‘fbound.lower’
to ‘-HUGE_VAL’ and ‘fbound.upper’ to ‘HUGE_VAL’.
These fields must only be used if ‘arg_type’ is ‘MU_OPT_FLOAT’
(*note Option Argument Types::).
‘const char *file_mode’
The file mode to pass to ‘fopen’ when opening a file argument.
*Note (libc)Opening Streams::.
This field must only be used if ‘arg_type’ is ‘MU_OPT_FILE’
(*note Option Argument Types::).
‘const MU_ENUM_VALUE *enum_values’
The enumeration specification. *Note Parsing Enums:: for more
information.
This field must only be used if ‘arg_type’ is ‘MU_OPT_ENUM’
(*note Option Argument Types::).
‘int enum_case_match’
If this is nonzero, enumerated arguments will be matched
against the values in ‘enum_values’ case sensitively.
Otherwise, matching will be case insensitive. *Note Parsing
Enums:: for more information.
This field must only be used if ‘arg_type’ is ‘MU_OPT_ENUM’
(*note Option Argument Types::).
‘const MU_OPT *subopts’
This is a list of valid suboptions for this option. *Note
Parsing Suboptions::.
This field must only be used if ‘arg_type’ is ‘MU_OPT_SUBOPT’
(*note Option Argument Types::).
‘const char *arg_help’
This is a string which will be displayed in the help message
as the argument for your option (*note Formatting Help::).
For example, ‘FILE’, ‘NAME’, or, if you're not feeling very
imaginative, ‘ARG’. This field may not contain newlines
(‘\n’).
If you leave this as ‘NULL’, a default will be chosen based on
‘arg_type’ (*note Option Argument Types::).
‘const char *help’
The full help text for your option, used when formatting the
help message (*note Formatting Help::). This text may make
references to the string passed in ‘arg_help’. There should
be no newlines in this string (even if it is quite long(1))
unless you really want a line break in a certain place.
Normally, you should just let line wrapping happen
automatically.
If this field is left as ‘NULL’, the option will not be
documented in either help or ‘man’ output (*note Formatting
Help::). Of course, the option will still be parsed as usual.
‘const char *negated_help’
The help text for the negated option. If this is left as
‘NULL’ and ‘help’ (see above) is not ‘NULL’, it will default
to ‘negate OPTION’, where OPTION is the non-negated option or
suboption (including aliases). However, if ‘negated_help’ is
‘NULL’ and ‘help’ is also ‘NULL’, neither the option nor the
negated option will be documented. If ‘negated_help’ is
non-‘NULL’ but ‘help’ is ‘NULL’, only the negated option will
be documented.
This field may only be used if ‘has_arg’ is ‘MU_OPT_NONE’ and
‘negatable’ is nonzero.
---------- Footnotes ----------
(1) You should try to keep the help text fairly short, though.
2.2 Aliases for Options and Environment Variables
=================================================
The fields ‘long_opt’, ‘subopt_name’, and ‘env_var’ of the ‘MU_OPT’
structure (*note Option Structure::) allow aliases separated by ‘|’.
The ‘short_opt’ field allows aliases to be specified as multiple
characters in the string (which must be terminated by a null byte).
For example, the string ‘abc’, when specified as the ‘short_opt’
field, indicates three equivalent short options: ‘-a’, ‘-b’, and ‘-c’.
In the ‘long_opt’ field, ‘foo|bar|baz’ would specify three equivalent
long options: ‘--foo’, ‘--bar’, and ‘--baz’. The same goes for
‘subopt_name’ and ‘env_var’ (but *note Parsing the Environment:: for
more information on environment variable aliases).
Duplicate aliases are not allowed, and will be diagnosed as an error.
For example, in the ‘short_opt’ field, ‘abcb’ will be diagnosed because
the ‘b’ is repeated. Likewise, ‘foo|bar|foo’ would be diagnosed in any
of the ‘long_option’, ‘subopt_name’, or ‘env_var’ fields. Empty aliases
are diagnosed as well (including the entire string being empty). So
‘foo||bar’ would be diagnosed in any of the ‘long_option’,
‘subopt_name’, or ‘env_var’ fields, because there is an empty alias
between ‘foo’ and ‘bar’. In any of the same fields, in addition to
‘short_opt’, the empty string (‘’) will be diagnosed as well. Leave a
field as ‘NULL’ if you don't want any options (or environment variables)
of that type.
2.3 Negatable Options
=====================
A “negatable†option is an option which can be specified later on the
command line in a different form, to negate the effect of a previous
specification. Short options are negated using ‘+’ rather than ‘-’ to
specify the option. Long options and suboptions must be prefixed with
‘no-’ or the specified negation prefixes (*note Negation Prefixes::).
For example,
$ prog --foo --no-foo
should act as though ‘--foo’ were never specified. Only negatable
options can be negated. For an option to be negatable, its ‘negatable’
field must be set to a nonzero value (*note Option Structure::).
Options that take arguments (i.e., options for which the ‘has_arg’ field
is not ‘MU_OPT_NONE’) may not be negated. Indeed, setting the
‘negatable’ field to _any_ value for an option which takes an argument
results in undefined behavior.
Environment variables may not be negated. The reason for this is
because it is not easy to control the order in which environment
variables appear. Thus, if environment variable negation were allowed
and ‘FOO’ were a negatable environment variable,
$ FOO= NO_FOO= prog
may or may not act as though ‘FOO’ were specified. So if an option
for which the ‘negatable’ field is nonzero also has a non-‘NULL’
‘env_var’ field, ‘NO_FOO’ will be ignored. Note, however, that the
‘callback_negatable’ callback should still be used (but it may be better
not to use callbacks at all; see below). Rather than having an
‘env_var’ field for a negatable option, it is instead better to make a
separate environment variable that has a boolean value (*note Option
Argument Types::).
Since environment variables may not be negated, specifying the
‘negatable’ field for an environment variable which has no equivalent
options is useless. Because of this, it is not allowed and will be
diagnosed.
When option parsing is finished, the value that the ‘found_opt’ field
points to (if any) will be nonzero if the last instance of the option
found on the command line was not negated, or zero if it was negated.
Negatable options should use the ‘callback_negatable’ field if they
are using a callback (*note Option Callbacks::), although it is usually
preferable not to use a callback. Suppose you have a certain negatable
option, and you want to, say, open a file when it is found. If you used
a callback, you would need to open the file whenever VALUE was nonzero,
and then close it again when it is zero. Although in this case this
would be fairly easy to implement (although far from ideal), it is still
much better to simply wait until option parsing is finished, and then
check the value that the ‘found_opt’ field points to.
Here is an example illustrating how to parse negatable options:
#include <stdio.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x{new,free} */
/* Print a message when we find the negatable option. Usually, we
shouldn't use a callback for negatable options, but we are just
using it to print a message. */
static int print_negatable(int value, void *data, char *err) {
printf(" Found the negatable option, and it was%s negated.\n",
value ? " not" : "");
return 0;
}
int main(int argc, char **argv) {
int found_negatable;
int ret;
const MU_OPT options[] = {
{
.short_opt = "n",
.long_opt = "negatable",
.has_arg = MU_OPT_NONE,
.negatable = 1,
.found_opt = &found_negatable,
.callback_negatable = print_negatable
},
{ 0 }
};
MU_OPT_CONTEXT *context;
/* Parse the options. */
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_PERMUTE);
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
if (MU_OPT_ERR(ret))
return 1;
printf("It appears that the negatable option was%s given.\n",
found_negatable ? "" : " not");
return 0;
}
Here is the output of the above program:
$ ./option-negatable
⊣ It appears that the negatable option was not given.
$ ./option-negatable --negatable -n --no-negatable +n
⊣ Found the negatable option, and it was not negated.
⊣ Found the negatable option, and it was not negated.
⊣ Found the negatable option, and it was negated.
⊣ Found the negatable option, and it was negated.
⊣ It appears that the negatable option was not given.
$ ./option-negatable -n +n --negatable
⊣ Found the negatable option, and it was not negated.
⊣ Found the negatable option, and it was negated.
⊣ Found the negatable option, and it was not negated.
⊣ It appears that the negatable option was given.
2.3.1 Negation Prefixes
-----------------------
By default, long options and suboptions are negated by prefixing them
with ‘no-’ (*note Negatable Options::). However, alternative negation
prefixes may be specified as well. For example, you might want to parse
options in a similar style to XBoard, with options negated by a single
‘x’ (*note (xboard)Options::).
Negation prefixes, like regular options, are case sensitive. Thus,
if you have a negation prefix of ‘no-’, ‘No-’ will not be recognized (or
will be treated as a separate option).
-- Function: int mu_opt_context_set_no_prefixes (MU_OPT_CONTEXT
*CONTEXT, ...)
-- Function: int mu_opt_context_set_no_prefix_array (MU_OPT_CONTEXT
*CONTEXT, char **STRINGS)
-- Function: int mu_subopt_context_set_no_prefixes (MU_SUBOPT_CONTEXT
*CONTEXT, ...)
-- Function: int mu_subopt_context_set_no_prefix_array
(MU_SUBOPT_CONTEXT *CONTEXT, char **STRINGS)
Set a list of negation prefixes in CONTEXT. In the case of
‘mu_opt_context_set_no_prefixes’ and
‘mu_subopt_context_set_no_prefixes’, the negation prefixes are
specified in the variable arguments. In the case of
‘mu_opt_context_set_no_prefix_array’ and
‘mu_subopt_context_set_no_prefix_array’, the negation prefixes are
specified in STRINGS. In both cases, the list of negation prefixes
must be terminated by ‘NULL’.
Duplicate negation prefixes are not allowed. If duplicates are
present in STRINGS or the variable arguments, ‘errno’ will be set
to ‘EINVAL’ and these functions will return nonzero.
Subsequent calls to these functions are allowed, but will overwrite
negation prefixes set by previous calls. However, it is *not*
allowed to call these functions after CONTEXT has been passed to
‘mu_parse_opts’ or ‘mu_parse_subopts’.
Here is an example of how alternative negation prefixes may be used:
#include <stdio.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x* */
/* Print a message when we find the negatable option. */
static int print_negatable(int value, void *data, char *err) {
printf(" Found the negatable option, and it was%s negated.\n",
value ? " not" : "");
return 0;
}
int main(int argc, char **argv) {
int ret;
const MU_OPT options[] = {
{
.short_opt = "n",
.long_opt = "negatable",
.has_arg = MU_OPT_NONE,
.negatable = 1,
.callback_negatable = print_negatable
},
{ 0 }
};
MU_OPT_CONTEXT *context;
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_PERMUTE);
/* Set the negation prefixes. This must be done *before*
mu_parse_opts() is called. */
mu_opt_context_xset_no_prefixes(context, "negate-", "no-", "x", NULL);
/* Now parse the options. */
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
if (MU_OPT_ERR(ret))
return 1;
return 0;
}
And the output:
$ ./negation-prefixes --negatable
⊣ Found the negatable option, and it was not negated.
$ ./negation-prefixes --negate-negatable
⊣ Found the negatable option, and it was negated.
$ ./negation-prefixes --no-negatable
⊣ Found the negatable option, and it was negated.
$ ./negation-prefixes --xnegatable
⊣ Found the negatable option, and it was negated.
$ ./negation-prefixes --foo-negatable
error→ ./negation-prefixes: '--foo-negatable': invalid option
2.4 Option Arguments
====================
Options can take arguments and environment variables can have values
(*note Parsing the Environment::). Some options and environment
variables require arguments or values, while others may optionally take
arguments or have values, while still others might take no arguments at
all or not allow any values. Mu supports all of these types of options
and environment variables through the ‘has_arg’ field of the ‘MU_OPT’
structure (*note Option Structure::).
-- Enumerated Type: enum MU_OPT_HAS_ARG
‘MU_OPT_NONE’
This indicates that an option takes no arguments. If the
‘MU_OPT_BUNDLE’ flag (*note Option Parsing Flags::) is _not_
specified, then any text following a short option which
doesn't take an argument will be an error.(1) An ‘=’ is an
error in a long option that does not take an argument, because
‘=’ is used to specify arguments to long options.
‘*has_arg’ will always be set to ‘0’ if ‘has_arg’ is not
‘NULL’.
‘MU_OPT_OPTIONAL’
This indicates that an option may take an argument, but that
the option doesn't require an argument. Even if the
‘MU_OPT_BUNDLE’ flag is passed (*note Option Parsing Flags::),
short options with optional arguments may not be bundled
except as the last option in a bundle. The reason for this is
as follows: Suppose short option ‘b’ takes an optional
argument. And suppose short options ‘a’ and ‘c’ take no
argument. Now what should ‘-abc’ mean (assuming
‘MU_OPT_BUNDLE’ was passed)? Is it three options without
arguments, ‘a’, ‘b’, and ‘c’? Or is it two options, ‘a’ and
‘b’, the latter of which taking an argument, ‘c’? It is in
fact the latter, two options ‘a’ and ‘b’, with ‘b’ taking an
argument, ‘c’. Note, however, that if ‘b’ is specified as the
last option like so: ‘-acb’, there is no ambiguity, because
there is nothing following the ‘b’ option (and if there is
text following it in another argument, it will be treated as a
positional argument; see below).
Short options taking an optional argument _must_ have their
arguments specified with the option itself. For example, if a
short option, ‘b’, takes an optional argument, it must be
specified as ‘-bARG’, not ‘-b ARG’. The reason for this is
because ‘-b ARG’ could be a short option ‘b’ with an argument
ARG, or a short option ‘b’ with no argument, and a positional
argument ARG. Likewise, long options taking optional
arguments must be specified as ‘--long=ARG’, not ‘--long ARG’.
If ‘has_arg’ is not ‘NULL’, then ‘*has_arg’ will be set to ‘1’
if the option has an argument, or ‘0’ if the option doesn't
have an argument.
‘MU_OPT_REQUIRED’
This indicates that an option requires an argument. If no
argument is specified, it is an error. Like short options
with optional arguments, short options with required arguments
may not be bundled except as the last option in a bundle. See
above for an explanation.
For short options with required arguments, the argument may be
passed with the option itself like so: ‘-rARG’, or immediately
after the argument like so: ‘-r ARG’. Arguments to long
options with required arguments may also be specified with the
option itself like so: ‘--required=ARG’, or immediately after
the argument like so: ‘--required ARG’.
‘*has_arg’ will always be set to ‘1’ if ‘has_arg’ is not
‘NULL’.
---------- Footnotes ----------
(1) But only if the text following the short option is in the same
argument as the option itself, e.g., ‘-oFOO’, not ‘-o FOO’. If the
following text is in a new argument, as in the latter case, it will be
treated as a positional argument, not an argument to ‘-o’.
2.4.1 Option Argument Types
---------------------------
Mu supports several option types, and more may be added in the future.
These types will automatically be processed from the string argument,
and the processed argument will be returned in ‘*arg’ if ‘arg’ is not
‘NULL’ (*note Option Structure::). ‘arg’ should be a pointer to a value
of the type indicated by the ‘arg_type’ field, which must be one of the
values in the table below. However, if ‘arg_type’ is ‘MU_OPT_SUBOPT’,
‘arg’ must not be used (*note Parsing Suboptions::). If an error occurs
while processing an argument, an error message will be printed to
standard error, and ‘mu_parse_opts’ will return an error code (*note
Option Parsing Errors::).
Unless otherwise specified, ‘*argstr’ will be set to the unprocessed
string argument if ‘argstr’ is not ‘NULL’ (*note Option Structure::).
However, if ‘arg_type’ is ‘MU_OPT_SUBOPT’, ‘argstr’ must not be used.
You can also parse your own types using callbacks (*note Option
Callbacks::).
-- Enumerated Type: enum MU_OPT_ARG_TYPE
‘MU_OPT_BOOL’
This is a boolean value. The type of ‘*arg’ should be ‘int’
and ‘bool_default’ should be used for the default value (*note
Option Structure::). If ‘MU_OPT_BOOL’ is given in the
‘arg_type’ field, the argument can either be ‘yes’ or ‘true’
for a true value, or ‘no’ or ‘false’ for a false value.
Matching is case insensitive and allows abbreviation.
If the argument is none of ‘yes’, ‘no’, ‘true’, or ‘false’, it
will be parsed as an integer (see below). Zero is false and
any other integer is true.
If the argument is not an integer either, that will be an
error.
‘MU_OPT_INT’
This is an integer value. The type of ‘*arg’ should be ‘long’
and ‘int_default’ should be used for the default value (*note
Option Structure::). The radix (or base) that the argument is
parsed as depends on the first non-whitespace characters after
an optional ‘+’ or ‘-’ sign. If these characters are ‘0x’ or
‘0X’, the integer is parsed as hexadecimal. Otherwise, if the
first character is ‘0’, and the following character is _not_
‘x’ or ‘X’, the integer will be parsed as octal. Otherwise,
the integer will be parsed as decimal. *Note (libc)Parsing of
Integers:: for more information on how integers are parsed.
If the parsed integer is outside the bounds specified by the
‘ibound’ field (*note Option Structure::), then that will be
treated as an error.
‘MU_OPT_FLOAT’
This is a floating-point value. The type of ‘*arg’ should be
‘double’ and ‘float_default’ should be used for the default
value (*note Option Structure::). The radix (or base) that
the argument is parsed as depends on the first non-whitespace
characters after an optional ‘+’ or ‘-’ sign. If these
characters are ‘0x’ or ‘0X’, the number is parsed as
hexadecimal. Otherwise, if the first character is ‘0’, and
the following character is _not_ ‘x’ or ‘X’, the number will
be parsed as octal. Otherwise, the number will be parsed as
decimal. *Note (libc)Parsing of Floats:: for more information
on how floating-point numbers are parsed. *Note (libc)Parsing
of Floats:: for more information on how floating-point numbers
are parsed.
If the parsed floating-point numebr is outside the bounds
specified by the ‘fbound’ field (*note Option Structure::),
then that will be treated as an error.
‘MU_OPT_STRING’
This is a string value. The type of ‘*arg’ should be ‘const
char *’ and ‘string_default’ should be used for the default
value (*note Option Structure::) (i.e., the type of ‘arg’
should be ‘const char **’). ‘*argstr’ (if ‘argstr’ is not
‘NULL’) will be set to the same value as ‘*arg’.
‘MU_OPT_FILE’
This is a file argument. The type of ‘*arg’ should be ‘FILE
*’ (i.e., the type of ‘arg’ should be ‘FILE **’) and
‘file_default’ should be used for the default value (*note
Option Structure::). ‘file_mode’ should be used for this type
and only for this type (*note Option Structure::).
‘file_mode’ describes the mode to use when opening the file,
and how ‘-’ should be handled. If ‘file_mode’ indicates that
the file should be opened in read-only mode, ‘-’ will be
handled as standard input. If ‘file_mode’ indicates that the
file should be opened in write-only mode, ‘-’ will be handled
as standard output. If ‘file_mode’ indicates that the file
should be opened for both reading and writing, ‘-’ will cause
an error.
If ‘argstr’ is not ‘NULL’, ‘*argstr’ will be set to ‘<stdin>’
if ‘-’ was handled as standard input, ‘<stdout>’ if ‘-’ was
handled as standard output, or the file name given as the
argument to the option if the argument was not ‘-’.
If an error occurs while opening a file, an error message will
be printed to standard error and ‘mu_parse_opts’ will return
an error code (*note Option Parsing Errors::).
For more information on how files are opened and how
‘file_mode’ is parsed, see *note (libc)Opening Streams::.
‘MU_OPT_DIRECTORY’
This is a directory argument. The type of ‘*arg’ should be
‘DIR *’ (i.e., the type of ‘arg’ should be ‘DIR **’) and
‘dir_default’ should be used for the default value (*note
Option Structure::). *Note (libc)Opening a Directory Stream::
for more information on how directories are opened.
If you'd like to know the name of the directory as given as
the argument to the option, you can use the ‘argstr’ field
(*note Option Structure::).
If an error occurs while opening a directory, an error message
will be printed to standard error and ‘mu_parse_opts’ will
return an error code (*note Option Parsing Errors::).
‘MU_OPT_ENUM’
This is an enumerated argument. The enumeration specification
is the ‘enum_values’ field (*note Option Structure::).
For more information, *Note Parsing Enums::.
‘MU_OPT_SUBOPT’
This indicates that the option takes suboptions as arguments.
Suboptions may not take suboptions as arguments. *Note
Parsing Suboptions:: for more information.
2.5 Option Callbacks
====================
Option callbacks are useful when you have more advanced option parsing
needs. Each option argument type has a different callback. There are
also callbacks for options which don't take arguments: ‘callback_none’
for non-negatable options, and ‘callback_negatable’ for negatable
options (*note Negatable Options::). All callback names mentioned are
members of the ‘MU_OPT’ structure.
For a callback that is called when a _positional_ argument is seen,
use ‘mu_opt_context_set_arg_callback’ (*note Ordered Option Parsing::).
The callback names and prototypes for each argument type are listed
below (although ‘MU_OPT_NONE’ is not a type, and should be passed in the
‘has_arg’ field of the ‘MU_OPT’ structure, not the ‘arg_type’ field):
‘MU_OPT_NONE’
If the ‘negatable’ field is zero (*note Option Structure::):
int (*callback_none) (void *DATA, char *ERR)
Otherwise, if ‘negatable’ is nonzero:
int (*callback_negatable) (int VALUE, void *DATA, char *ERR)
‘MU_OPT_BOOL’
int (*callback_bool) (int HAS_ARG, int ARG, void *DATA, char *ERR)
‘MU_OPT_INT’
int (*callback_int) (int HAS_ARG, long ARG, void *DATA, char *ERR)
‘MU_OPT_FLOAT’
int (*callback_float) (int HAS_ARG, double ARG, void *DATA, char
*ERR)
‘MU_OPT_STRING’
int (*callback_string) (int HAS_ARG, const char *ARG, void *DATA,
char *ERR)
‘MU_OPT_FILE’
int (*callback_file) (int HAS_ARG, const char *FILENAME, FILE
*FILE, void *DATA, char *ERR)
‘MU_OPT_DIRECTORY’
int (*callback_directory) (int HAS_ARG, const char *DIRNAME, DIR
*DIRECTORY, void *DATA, char *ERR)
‘MU_OPT_ENUM’
int (*callback_enum) (int HAS_ARG, int ARG, void *DATA, char *ERR)
‘MU_OPT_SUBOPT’
int (*callback_subopt) (int HAS_ARG, void *DATA, char *ERR)
A callback will be called as soon as an option is found, so callbacks
are guaranteed to be called in the same order as the options appear on
the command line. This means that if an option takes suboptions as
arguments, the callback for the main option will be called before the
callbacks for the suboptions (*note Parsing Suboptions::). The HAS_ARG
parameter will be passed as ‘1’ if the option has an argument, or ‘0’ if
the option doesn't have an argument (except for ‘callback_none’ which
doesn't have a HAS_ARG parameter).
If the option has an argument, ARG will be set to that argument,
except in the case of suboptions (*note Parsing Suboptions::). In the
case of ‘callaback_file’ and ‘callback_directory’, FILENAME or DIRNAME
will be set to the name of the file or directory respectively.(1) For
‘callback_negatable’, VALUE will be zero if the option was negated, or
nonzero if it wasn't (*note Negatable Options::).
If you need to provide extra information to a callback, provide it in
the ‘cb_data’ field of the ‘MU_OPT’ structure. This will then be passed
as the DATA parameter to a callback. Note: a callback should _not_ free
this parameter even if it is dynamically allocated. In the case that
‘cb_data’ is dynamically allocated and/or contains dynamically allocated
data, you should also set the ‘cb_data_destructor’ field to a function
which will free all dynamically allocated data in ‘cb_data’.
When you call ‘mu_opt_context_free’ (*note Parsing Options and
Environment::) or ‘mu_subopt_context_free’ (*note Parsing Suboptions::),
each ‘cb_data_destructor’ field is called with the corresponding
‘cb_data’ in order to free that data. If an error occurs while freeing
callback data (for example, an error closing a file),
‘cb_data_destructor’ should return nonzero. Otherwise,
‘cb_data_destructor’ should return zero.
For ‘callback_file’ and ‘callback_directory’, the FILE or DIRECTORY
argument *will be closed* after the callback returns if you leave the
‘arg’ field of the ‘MU_OPT’ structure as ‘NULL’ (*note Option
Structure::). So you must not close the FILE or DIRECTORY argument in
the callback.
You also must *not* use the ‘cb_data’ field to get the opened
file/directory. For example, the following code is _wrong_:
#include <stdio.h>
#include <string.h>
#include <errno.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x{new,free} */
int file_callback(int has_arg, const char *filename,
FILE *file, void *data, char *err) {
/* Make sure the file is named "foo". */
if (strcmp(filename, "foo")) {
snprintf(err, MU_OPT_ERR_MAX, "file is not named \"foo\"");
return 1;
}
/* It is named "foo"; return `file' in `*data'.
This is WRONG! Do not do this! */
*(FILE **)data = file;
return 0;
}
int main(int argc, char **argv) {
FILE *file = NULL;
char buf[256];
size_t size;
int ret;
const MU_OPT options[] = {
{
.short_opt = "f",
.long_opt = "file",
.has_arg = MU_OPT_REQUIRED,
.arg_type = MU_OPT_FILE,
.file_mode = "r",
.callback_file = file_callback,
.cb_data = &file
},
{ 0 }
};
MU_OPT_CONTEXT *context;
/* Parse the options. */
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_PERMUTE);
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
if (MU_OPT_ERR(ret))
return 1;
if (!file) {
/* We weren't passed the `-f' option. */
return 0;
}
/* Read the file. This invokes UNDEFINED BEHAVIOR because
`file' was already closed by `mu_parse_opts'! */
size = fread(buf, sizeof(*buf), sizeof(buf), file);
if (ferror(file)) {
fprintf(stderr, "%s: cannot read foo: %s\n",
argv[0], strerror(errno));
return 1;
}
fclose(file);
/* Print the contents of the file to standard output. */
fwrite(buf, sizeof(*buf), size, stdout);
return 0;
}
When this program is run, it invokes undefined behavior. The correct
way to do this is to _not_ use the ‘cb_data’ field, and instead set the
‘arg’ field to ‘&file’. This way, ‘mu_parse_opts’ will not close the
file or directory after the callback returns.
If a callback needs to indicate an error (if its argument is in the
wrong format, for example), it should return nonzero. Otherwise, on
success, it should return ‘0’. If a callback returns nonzero, you must
write an error string to ERR which will then be used by ‘mu_parse_opts’
to print an error message. You must not write more than
‘MU_OPT_ERR_MAX’ characters to ERR (including the terminating null
byte). However, if you write exactly ‘MU_OPT_ERR_MAX’ bytes to ERR, you
need not terminate ERR with a null byte.
Below is an example of how to use callbacks. Of course, this trivial
example would be better expressed using enumerated argument parsing
(*note Parsing Enums::).
#include <stdio.h>
#include <string.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x{new,free} */
enum selection { FOO, BAR, BAZ };
/* Parse a selection. `has_arg' will always be true because the option
takes a required argument. */
int parse_selection(int has_arg, const char *arg,
void *data, char *err) {
enum selection sel;
if (!strcmp(arg, "foo"))
sel = FOO;
else if (!strcmp(arg, "bar"))
sel = BAR;
else if (!strcmp(arg, "baz"))
sel = BAZ;
else {
/* `err' will be used by `mu_parse_opts' to print an error
message. */
snprintf(err, MU_OPT_ERR_MAX, "invalid selection: %s", arg);
/* Indicate to `mu_parse_opts' that an error occured by returning
a nonzero value. */
return 1;
}
/* Store the selection in `*data'. */
*(enum selection *)data = sel;
/* Success! */
return 0;
}
int main(int argc, char **argv) {
enum selection sel;
int found_sel;
int ret;
const MU_OPT options[] = {
{
.short_opt = "s",
.long_opt = "selection",
.has_arg = MU_OPT_REQUIRED,
.arg_type = MU_OPT_STRING,
.found_arg = &found_sel,
.callback_string = parse_selection,
.cb_data = &sel
},
{ 0 }
};
MU_OPT_CONTEXT *context;
/* Parse the options. */
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_PERMUTE);
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
if (MU_OPT_ERR(ret))
return 1; /* `mu_parse_opts' will print an error message for us */
if (found_sel) {
/* Print the selection. */
fputs("You selected: ", stdout);
switch (sel) {
case FOO:
puts("FOO");
break;
case BAR:
puts("BAR");
break;
case BAZ:
puts("BAZ");
break;
default:
puts("an unknown value!"); /* This should not happen */
}
}
else
puts("You didn't select anything.");
return 0;
}
Here is what the output of the example program looks like:
$ ./option-callback
⊣ You didn't select anything.
$ ./option-callback -s foo
⊣ You selected: FOO
$ ./option-callback --selection=bar
⊣ You selected: BAR
$ ./option-callback -s qux
error→ ./option-callback: invalid selection: qux
$ ./option-callback -s
error→ ./option-callback: '-s': option requires argument
---------- Footnotes ----------
(1) However, for ‘callback_file’, FILENAME might be ‘<stdin>’ or
‘<stdout>’ when FILE is standard input or standard output respectively.
*Note Option Argument Types::.
2.6 Parsing Enumerated Arguments to Options
===========================================
It is often useful to have an option which takes an argument which is a
string that is restricted to a set of values. For example, GNU ‘ls’
(and many other programs) take a ‘--color’ option, which has an argument
that can be ‘always’, ‘auto’, or ‘never’ (in addition to various
synonyms). Mu supports similar argument parsing, called “enumerated
argumentsâ€.
Names and values for enumerated types are specified in the
‘enum_values’ field of the ‘MU_OPT’ structure (*note Option
Structure::). ‘enum_values’ is an array of ‘MU_ENUM_VALUE’ structures
as defined below. ‘enum_values’ is terminated by an element with a
‘name’ field of ‘NULL’.
If the ‘enum_case_match’ field of the ‘MU_OPT’ structure is nonzero
(*note Option Structure::), matching is case sensitive. Otherwise,
matching is case insensitive.
Like long options and suboptions, abbreviation is allowed when
passing enumerated arguments, as long as it is not ambiguous.
-- Data Type: MU_ENUM_VALUE
Unlike ‘MU_OPT’ (*note Option Structure::), this structure is
simple and it's organization is guaranteed. Therefore, you may use
positional initializers to initialize this structure. Of course,
you can still use designated initializers if you prefer.
‘const char *name’
This field specifies the name to match against when parsing
the argument. Like long options, suboptions, and environment
variables, ‘name’ may have aliases separated by ‘|’ (*note
Option Aliases::). Alternatively, aliases can be specified by
using separate entries with the same ‘value’ (see below).
Duplicates in this field, either duplicate aliases or
duplicates between entries, are not allowed. Note that if
‘enum_case_match’ is zero, case is not considered. So, if
‘enum_case_match’ is zero, you cannot have two entries, ‘foo’
and ‘FOO’, nor can you have two aliases specified as
‘foo|FOO’.
‘int value’
This is the value of the enumeration. It is the value passed
as the ARG parameter of ‘callback_enum’ (*note Option
Callbacks::), and, if the ‘arg’ field of the ‘MU_OPT’
structure is not ‘NULL’, it is the value stored in ‘*arg’.
The following example illustrates how to use both case insensitive
enumerated argument parsing, and case sensitive enumerated argument
parsing:
#include <stdio.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x{new,free} */
enum selection { FOO, BAR, BAZ };
int main(int argc, char **argv) {
enum selection sel;
int found_sel;
int ret;
const MU_ENUM_VALUE enum_table[] = {
/* Aliases can be specified for enumerated arguments. */
{ "foo|alias-foo", FOO },
{ "bar", BAR },
/* Aliases can alternatively be specified like this. */
{ "alias-bar", BAR },
{ "baz", BAZ },
/* This terminates the enumeration specification. */
{ 0 }
};
const MU_OPT options[] = {
{
.short_opt = "s",
.long_opt = "selection",
.has_arg = MU_OPT_REQUIRED,
.arg_type = MU_OPT_ENUM,
/* This indicates that matching should be case insensitive. */
.enum_case_match = 0,
.enum_values = enum_table,
.found_arg = &found_sel,
.arg = &sel
},
{
.short_opt = "c",
.long_opt = "case-selection",
.has_arg = MU_OPT_REQUIRED,
.arg_type = MU_OPT_ENUM,
/* This indicates that matching should be case sensitive. */
.enum_case_match = 1,
.enum_values = enum_table,
.found_arg = &found_sel,
.arg = &sel
},
{ 0 }
};
MU_OPT_CONTEXT *context;
/* Parse the options. */
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_PERMUTE);
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
if (MU_OPT_ERR(ret))
return 1;
if (found_sel) {
/* Print the selection. */
fputs("You selected: ", stdout);
switch (sel) {
case FOO:
puts("FOO");
break;
case BAR:
puts("BAR");
break;
case BAZ:
puts("BAZ");
break;
default:
/* This is guaranteed not to happen. */
puts("an unknown value!");
}
}
else
puts("You didn't select anything.");
return 0;
}
Here is the output of the above example, to show exactly how
enumerated arguments are parsed:
$ ./option-enum --selection=foo
⊣ You selected: FOO
$ ./option-enum --selection=alias-foo
⊣ You selected: FOO
$ ./option-enum --selection=alias-bar
⊣ You selected: BAR
$ ./option-enum --selection=bAr
⊣ You selected: BAR
$ ./option-enum --selection=Ba
error→ ./option-enum: 'Ba': argument for '--selection' is ambiguous; possibilities:
error→ bar
error→ baz
$ ./option-enum --selection=qux
error→ ./option-enum: 'qux': invalid argument for '--selection'; must be one of 'foo', 'bar', 'alias-bar', or 'baz'
$ ./option-enum --case-selection=FoO
error→ ./option-enum: 'FoO': invalid argument for '--case-selection'; must be one of 'foo', 'bar', 'alias-bar', or 'baz'
$ ./option-enum --case-selection=foo
⊣ You selected: FOO
2.7 Parsing Suboptions
======================
Sometimes you may want to have an option which takes suboptions as
arguments. You can do this through the ‘subopts’ field of the ‘MU_OPT’
structure. The ‘subopts’ field is a list of ‘MU_OPT’s, terminated by a
suboption with all fields equal to ‘0’. Suboptions are in every way
like regular options, except that they may not have suboptions of their
own and they must use the ‘subopt_name’ field instead of ‘short_opt’ or
‘long_opt’. *Note Option Structure::.
Suboptions may also specify the ‘env_var’ field for an equivalent
environment variables as well. Environment variables may also take
suboptions as a value. *Note Parsing the Environment::.
*Note:* even though environment variables may be specified for
suboptions, you may not have a suboption which _only_ specifies an
environment variable. I.e., you may not have a suboption which has no
‘subopt_name’ field (such an option will be considered as a terminator
for the suboption list). If you want to do this, use a regular option
instead.
Options which take suboptions as arguments may use the
‘callback_subopt’ field as a callback (*note Option Callbacks::). If a
callback is used and the option is found on the command line (or in the
environment for an environment variable), the callback for that option
is guaranteed to be called _before_ any callbacks for the suboptions
themselves. Note, however, that if a suboption has an equivalent
environment variable (using the ‘env_var’ field), the callback for the
option which takes that suboption as an argument will *not be called at
all* (though the callback for the suboption will be called). Indeed, it
is impossible to call the callback for the option which takes the
suboption as an argument, because two different options with different
callbacks may take the same suboptions as arguments. Nor would it make
any sense, because the option never actually appeared on the command
line (or environment).
Suboptions are specified as a comma-separated list, with ‘=’ used to
specify arguments. The commas must not contain spaces around them, and
arguments cannot be specified any other way than with ‘=’.
Suboptions, like long options, may be abbreviated as long as they are
not ambiguous. Note that this is in contrast to ‘getsubopt’, which does
not allow abbreviation (*note (libc)Suboptions::).
Like regular options, suboptions should use the ‘help’ field, which
will be used in the help message (*note Formatting Help:: and *note
Option Structure::). Suboptions may also use the ‘arg_help’ field if
they take arguments (*note Option Arguments::).
Normally, suboptions are parsed by ‘mu_parse_opts’ from an argument
to a regular option, using the ‘subopts’ field. However, you may also
parse suboptions in a user-specified string as well. Doing so is not
too dissimilar from parsing regular options.
-- Data Type: MU_SUBOPT_CONTEXT
This is an opaque context for parsing suboptions. It is allocated
using ‘mu_subopt_context_new’ and freed using
‘mu_opt_context_free’.
-- Function: MU_SUBOPT_CONTEXT * mu_subopt_context_new (const char
*PROG_NAME, const char *SUBOPTSTR,
const MU_OPT *SUBOPTS)
Allocate and return a new suboption parsing context. The name the
program was invoked as should be passed in PROG_NAME (normally
‘argv[0]’), and is used for error reporting.
The suboptions will be parsed in SUBOPTSTR. A copy of SUBOPTSTR
will be made, so you need not worry about it going out of scope or
being modified (this copy will be freed by
‘mu_subopt_context_free’). The suboptions are specified in
SUBOPTS.
-- Function: int mu_subopt_context_free (MU_SUBOPT_CONTEXT *CONTEXT)
Free the suboption context, CONTEXT. Callback data is freed as for
‘mu_opt_context_free’ (*note Parsing Options and Environment::).
Like ‘mu_opt_context_free’, ‘mu_subopt_context_free’ will return
nonzero if any of the destructors returned nonzero, or zero if all
destructors returned zero. Also like ‘mu_opt_context_free’, all
destructors are called even if one or more of them return nonzero.
-- Function: int mu_parse_subopts (MU_SUBOPT_CONTEXT *CONTEXT)
Parse the suboptions given in CONTEXT. Use ‘mu_subopt_context_new’
(see above) to create the context. Zero is returned on success, or
an error code on error (*note Option Parsing Errors::).
Note that you may not call this function more than once. To do so
is an error and will be diagnosed.
The following example illustrates the use of suboptions:
#include <stdio.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x* */
int subopt_none(void *data, char *err) {
puts("suboption found: none");
return 0;
}
int subopt_opt(int has_arg, const char *arg,
void *data, char *err) {
puts("suboption found: opt");
if (has_arg)
printf("argument: %s\n", arg);
return 0;
}
int subopt_req(int has_arg, const char *arg,
void *data, char *err) {
printf("suboption found: req\nargument: %s\n", arg);
return 0;
}
int main(int argc, char **argv) {
int ret;
/* These are the suboptions that can be passed to the `-o'
option. They are specified just like regular options, except
that `subopt_name' is used instead of `long_opt' or
`short_opt', and they may not have suboptions of their
own. */
const MU_OPT suboptions[] = {
{
.subopt_name = "none",
.has_arg = MU_OPT_NONE,
.callback_none = subopt_none,
.help = "a suboption taking no arguments"
},
{
.subopt_name = "opt",
.has_arg = MU_OPT_OPTIONAL,
.arg_type = MU_OPT_STRING,
.callback_string = subopt_opt,
.help = "a suboption taking an optional argument"
},
{
.subopt_name = "req",
.has_arg = MU_OPT_REQUIRED,
.arg_type = MU_OPT_STRING,
.callback_string = subopt_req,
.help = "a suboption taking a required argument"
},
{ 0 }
};
const MU_OPT options[] = {
{
.short_opt = "o",
.long_opt = "options",
.has_arg = MU_OPT_REQUIRED,
.arg_type = MU_OPT_SUBOPT,
.subopts = suboptions,
.help = "a regular option which takes suboptions"
},
{ 0 }
};
MU_OPT_CONTEXT *context;
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_PERMUTE);
/* Add the help option. */
mu_opt_context_add_help(context, NULL, NULL, "Parse suboptions.",
NULL, "1", NULL, NULL, NULL);
mu_opt_context_xadd_help_options(context, MU_HELP_BOTH);
/* Parse the options. */
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
if (MU_OPT_ERR(ret))
return 1;
return 0;
}
And here is the output of the example program (note, the ‘COLUMNS’
environment variable is set to 65 so that the help message will look
good in this manual):
$ COLUMNS=65
$ export COLUMNS
$ ./subopts -o none,opt=foo
⊣ suboption found: none
⊣ suboption found: opt
⊣ argument: foo
$ ./subopts -o req
error→ ./subopts: 'req': suboption requires argument
$ ./subopts --help
⊣ Usage: ./subopts [OPTION]...
⊣ Parse suboptions.
⊣
⊣ Mandatory arguments to long options are mandatory for short options too.
⊣ -o, --options=SUBOPTS a regular option which takes suboptions
⊣ -h, --help[=plain|man] print this help in plain text format if 'plain', or as a man(1) page if
⊣ 'man'; if the argument is omitted, it will default to 'plain'.
⊣
⊣ Suboptions for -o, --options:
⊣ none a suboption taking no arguments
⊣ opt[=STRING] a suboption taking an optional argument
⊣ req=STRING a suboption taking a required argument
2.8 Parsing the Environment
===========================
In addition to parsing options, ‘mu_parse_opts’ supports parsing
environment variables as well. Environment variables are specified
using the ‘env_var’ field (*note Option Structure::). Values of
environment variables are specified in the same way as arguments are
specified to options (*note Option Arguments::).
Unlike options, environment variables are parsed in the program
environment (or the ENVIRONMENT parameter to
‘mu_opt_context_new_with_env’), rather than in ARGV (*note Parsing
Options and Environment::). And unlike long options and suboptions,
environment variables may *not* be abbreviated. And whereas an invalid
_option_ will cause an error, an invalid _environment variable_ will be
ignored.
Environment variables may be specified for suboptions, and an
environment variable may take suboptions as a value as well. For
example, you might have an environment variable, ‘ENV’, which takes a
suboption ‘foo’, which itself takes an optional string argument, say.
And suppose ‘foo’ has an equivalent environment variable, ‘ENV_FOO’.
Then you might specify a value ‘bar’ to the ‘foo’ suboption either by
specifying a value to ‘ENV’ like this: ‘ENV=foo=bar’, or by specifying a
value directly to ‘ENV_FOO’ like this: ‘ENV_FOO=bar’. The example shows
how to do this as well. *Note Parsing Suboptions:: for more information
on suboptions.
Environment variables are always parsed before command line options.
Environment variables and long/short options may be specified in the
same option, but if this is the case, the command line option(s) will
take precedence over the environment variable, since the environment
variables will always be parsed first.
If an environment variable has aliases (*note Option Aliases::),
aliases specified first will take precedence. For example, if an
environment variable is specified as ‘FOO|BAR’, and both ‘FOO’ and ‘BAR’
are in the environment, then the value of ‘FOO’ will take precedence
because it was specified as an alias before ‘BAR’. Note also that if
both ‘FOO’ and ‘BAR’ are specified in the environment, the value of
‘BAR’ will be completely ignored. The callback (if any) will only be
called once, for ‘FOO’ (*note Option Callbacks::).
Another thing to note is that if you have an environment variable
with a ‘has_arg’ value of ‘MU_OPT_NONE’, then if that environment
variable is encountered, and it has a value other than the empty string,
that will cause an error. This is not very user-friendly behavior, and
you might consider using a ‘has_arg’ of ‘MU_OPT_OPTIONAL’ and an
‘arg_type’ of ‘MU_OPT_BOOL’. Then, if the environment variable has no
value, you can default to true. This is more user-friendly, because
things like ‘ENV_VAR=yes’ or ‘ENV_VAR=no’ will do what is expected
(assuming your environment variable is called ‘ENV_VAR’).
Traditionally, environment variable names are in ALL CAPS.
Here is an example of how environment variables can be parsed:
#include <stdio.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x* */
/* Print a message when an option is found. */
int print_opt(int has_arg, const char *arg,
void *data, char *err) {
const char *name = data;
printf("Found an option/environment variable '%s'", name);
if (has_arg)
printf(" with an argument '%s'", arg);
putchar('\n');
return 0;
}
int main(int argc, char **argv) {
int ret;
const MU_OPT suboptions[] = {
{
.subopt_name = "subopt",
/* Suboptions can have environment variables as well. */
.env_var = "ENV_SUBOPT",
.has_arg = MU_OPT_OPTIONAL,
.arg_type = MU_OPT_STRING,
.callback_string = print_opt,
.cb_data = "a suboption",
.help =
"a suboption with an equivalent environment variable"
},
{ 0 }
};
const MU_OPT options[] = {
{
.short_opt = "a",
.long_opt = "an-option",
/* AN_ENV_VAR will always take precedence over ALIAS since it is
specified first below. */
.env_var = "AN_ENV_VAR|ALIAS",
.has_arg = MU_OPT_OPTIONAL,
.arg_type = MU_OPT_STRING,
.callback_string = print_opt,
.cb_data = "an option",
.help =
"an option with an equivalent environment variable"
},
{
.short_opt = "b",
.long_opt = "another-option",
.has_arg = MU_OPT_OPTIONAL,
.arg_type = MU_OPT_STRING,
.callback_string = print_opt,
.cb_data = "another option",
.help =
"an option without an equivalent environment variable"
},
{
.env_var = "ANOTHER_ENV_VAR",
.has_arg = MU_OPT_REQUIRED,
/* Environment variables can have suboptions as well. */
.arg_type = MU_OPT_SUBOPT,
.subopts = suboptions,
.help =
"an environment variable (which takes "
"suboptions) without an equivalent option"
},
{ 0 }
};
MU_OPT_CONTEXT *context;
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_PERMUTE);
/* Add the help option. */
mu_opt_context_add_help(context, NULL, NULL,
"Parse options and environment variables.",
NULL, "1", NULL, NULL, NULL);
mu_opt_context_xadd_help_options(context, MU_HELP_BOTH);
/* Parse the options. */
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
if (MU_OPT_ERR(ret))
return 1;
return 0;
}
And here is the output of the above program (note, the ‘COLUMNS’
environment variable is set to 65 so that the help message will look
good in this manual):
$ COLUMNS=65
$ export COLUMNS
$ AN_ENV_VAR=foo ./environ --an-option=bar --another-option=baz
⊣ Found an option/environment variable 'an option' with an argument 'foo'
⊣ Found an option/environment variable 'an option' with an argument 'bar'
⊣ Found an option/environment variable 'another option' with an argument 'baz'
$ ANOTHER_ENV_VAR=subopt=foo ./environ
⊣ Found an option/environment variable 'a suboption' with an argument 'foo'
$ ENV_SUBOPT=foo ./environ
⊣ Found an option/environment variable 'a suboption' with an argument 'foo'
# AN_ENV_VAR will always take precedence over ALIAS. Also note that
# the callback is only called once, even though both aliases are
# specified.
$ AN_ENV_VAR=foo ALIAS=bar ./environ
⊣ Found an option/environment variable 'an option' with an argument 'foo'
$ ALIAS=bar AN_ENV_VAR=foo ./environ
⊣ Found an option/environment variable 'an option' with an argument 'foo'
$ ./environ --help
⊣ Usage: ./environ [OPTION]...
⊣ Parse options and environment variables.
⊣
⊣ -a, --an-option[=STRING] an option with an equivalent environment variable
⊣ -b, --another-option[=STRING] an option without an equivalent environment variable
⊣ -h, --help[=plain|man] print this help in plain text format if 'plain', or as a man(1)
⊣ page if 'man'; if the argument is omitted, it will default to
⊣ 'plain'.
⊣
⊣ Suboptions for ANOTHER_ENV_VAR:
⊣ subopt[=STRING] a suboption with an equivalent environment variable
⊣
⊣ ENVIRONMENT
⊣
⊣ AN_ENV_VAR, ALIAS[=STRING] an option with an equivalent environment variable
⊣ ANOTHER_ENV_VAR=SUBOPTS an environment variable (which takes suboptions) without an
⊣ equivalent option
⊣ ENV_SUBOPT[=STRING] a suboption with an equivalent environment variable
2.9 Option Parsing Flags
========================
There are several flags which affect option parsing in different ways.
These flags are passed in the FLAGS parameter to ‘mu_opt_context_new’
(*note Parsing Options and Environment::).
-- Constant: MU_OPT_PERMUTE
This flag indicates that ‘mu_parse_opts’ should rearrange ARGV so
that the options are at the beginning, and positional arguments are
at the end.(1) If this flag is _not_ given, option parsing will
stop as soon as the first non-option argument is encountered.
Option parsing will also stop when the string ‘--’ is encountered,
whether or not this flag was given. The ‘--’ string will be
treated as an option, i.e., it will be counted in the return value
of ‘mu_parse_opts’ and, if this flag is set, it will be moved
before all the other positional arguments in ARGV.
If the environment variable ‘POSIXLY_CORRECT’ is set, or the
‘MU_OPT_STOP_AT_ARG’ flag is used, ‘mu_parse_opts’ will act as
though this flag were not given even if it was. Note that
‘POSIXLY_CORRECT’ is searched for in the ENV parameter given to
‘mu_opt_context_new_with_env’, or in the program environment if no
ENV parameter is given or if ‘mu_opt_context_new’ was used to
create the option parsing context. If you want to ignore
‘POSIXLY_CORRECT’ entirely, use the ‘MU_OPT_IGNORE_POSIX’ flag.
-- Constant: MU_OPT_BUNDLE
This flag enables bundling of short options. Without this flag,
long options may be specified with a single ‘-’ or ‘--’. When this
flag is set, long options may only be specified with ‘--’.
So when this flag is set, ‘-abc’ will be treated as three short
options, ‘a’, ‘b’, and ‘c’ (assuming that ‘a’ and ‘b’ don't take
arguments(2)), whereas without this flag, ‘-abc’ will be treated as
a single long option, ‘abc’.
Note that when this flag is _not_ set, short options with optional
arguments take precedence over long options. So, if there is a
short option, ‘o’, which takes an optional argument, and another
long option, ‘option’ (it doesn't matter whether it takes an
argument or not), then the string ‘-option’ is a short option, ‘o’
with an argument ‘ption’.
While this may seem counter-intuitive at first, the reason for this
seemingly strange behavior becomes apparent when you consider a
short option, ‘o’, which takes an optional argument and a long
option, ‘option’. (Again, it doesn't matter whether the long
option takes an argument or not.) Suppose that instead, long
options took precedence over short ones.(3) Now lets look at the
‘-option’ example again. It would be parsed as a single long
option, ‘option’. But what if you wanted to pass the ‘o’ short
option an argument ‘ption’? Or indeed, even just ‘p’? It would be
parsed as a long option, ‘option’. So there is *no possible way*
to pass an argument to the ‘o’ short option such that ‘ption’
begins with that argument (or _is_ the argument). But, you ask,
couldn't you write ‘-o ption’? You could, if the ‘o’ short option
takes a required argument, but not if it takes an optional
argument, because optional arguments to short options are required
to be specified as part of the option itself (*note Option
Arguments::). Note that you can still write the ‘option’ long
option as ‘--option’, which is unambiguous, so there is no issue.
Since this behavior can be confusing and counter-intuitive, long
options take precedence when the short option that would match
takes a required argument, and the long option matches exactly.
Going back to the above example, if the ‘o’ short option instead
took a required argument, ‘-option’ would be the long option
‘option’, rather than the short option ‘o’, with an argument
‘ption’. Note, however, that ‘-opt’ would be the ‘o’ short option
with an argument ‘pt’. Also note that if the ‘option’ long option
did not exist, ‘-option’ _would_ be the short option ‘o’ with an
argument ‘ption’. If you want to avoid ambiguity, you should
always pass required arguments to short options in the next
argument, and precede long options with two dashes like so: ‘-o ARG
--option’.
-- Constant: MU_OPT_CONTINUE
This flag should be used if you are going to call ‘mu_parse_opts’
more than once. *Note Ordered Option Parsing:: for more
information on how to use this flag correctly.
If the ‘POSIXLY_CORRECT’ environment variable is set, or the
‘MU_OPT_STOP_AT_ARG’ flag is passed, all arguments after the first
non-option arguments will be treated as non-option arguments as
well. Note that ‘POSIXLY_CORRECT’ is searched for in the ENV
parameter given to ‘mu_opt_context_new_with_env’, or in the program
environment if no ENV parameter is given or if ‘mu_opt_context_new’
was used to create the option parsing context. If you want to
ignore ‘POSIXLY_CORRECT’ entirely, use the ‘MU_OPT_IGNORE_POSIX’
flag.
-- Constant: MU_OPT_ALLOW_INVALID
This flag makes ‘mu_parse_opts’ treat invalid options as positional
arguments. It can be useful if you are writing a function which
parses some options, but then leaves the rest for the caller to
parse. An example of a function which does this (although it does
not use Mu) is ‘gtk_init’ (see section ‘Main loop and Events’ in
‘GTK+ 3 Reference Manual’).
Note: if you use ‘mu_opt_context_add_help_options’, the help option
will only print the help for the context you called
‘mu_opt_context_add_help_options’ with.
‘mu_opt_context_add_help_options’ has no way of knowing what
options will be parsed in the future. So if you are writing a
function like that described above, you may wish instead to make
your function take an option context as a parameter, and then add
some standard ones using ‘mu_opt_context_add_options’ (*note
Parsing Options and Environment::).
-- Constant: MU_OPT_IGNORE_POSIX
Ignore the ‘POSIXLY_CORRECT’ environment variable even if it is
set. This flag can be used for programs for which it would not
make sense to parse options in a POSIXly correct way. For example,
you might have an option which acts on the last positional argument
given before it.
-- Constant: MU_OPT_STOP_AT_ARG
Stop parsing options after the first positional argument. I.e.,
act as though the ‘POSIXLY_CORRECT’ environment variable were set.
If this flag is used, ‘MU_OPT_IGNORE_POSIX’ has no effect.
Note that this behavior is the default, unless the ‘MU_OPT_PERMUTE’
flag is used, the ‘MU_OPT_CONTINUE’ flag is used, and/or an
argument callback is used (*note Ordered Option Parsing::).
---------- Footnotes ----------
(1) Positional arguments are not rearranged internally, however.
I.e., the positional arguments are guaranteed to be in the same order as
they originally appeared in, even if ARGV was rearranged.
(2) *Note Option Arguments:: for an explanation of why options ‘a’
and ‘b’ cannot take arguments.
(3) And indeed, this is the way GNU's ‘getopt_long_only’ function
works. *Note (libc)Getopt Long Options::, near the bottom.
2.10 Ordered Option Parsing
===========================
Sometimes it is useful to know where options appear on the command line.
You can tell in which order _options_ (and suboptions) appear by taking
advantage of the fact that callbacks (*note Option Callbacks::) are
called in the same order that the corresponding options appear on the
command line. However, if you want to determine the ordering of
non-option _positional arguments_ as well as options, you must instead
use an “argument callbackâ€, or use the ‘MU_OPT_CONTINUE’ flag (*note
Option Parsing Flags::).
To use an argument callback, you must use the
‘mu_opt_context_set_arg_callback’ function.
-- Function: void mu_opt_context_set_arg_callback (MU_OPT_CONTEXT
*CONTEXT, int CALLBACK (const char *ARG, void *DATA, char
*ERR), void *DATA, int DESTRUCTOR (void *DATA))
This function sets an argument callback in CONTEXT. CONTEXT must
not have been created with the ‘MU_OPT_CONTINUE’ flag (*note Option
Parsing Flags::), and it must never have been passed to
‘mu_parse_opts’ (*note Parsing Options and Environment::).
CALLBACK will be called for each positional argument found when
‘mu_parse_opts’ is called. CALLBACK may not be ‘NULL’. DATA will
be passed to CALLBACK as the DATA argument. When CONTEXT is
destroyed using ‘mu_opt_context_free’, DESTRUCTOR will be called
with DATA passed as its DATA argument.
CALLBACK should indicate success by returning zero. If CALLBACK
fails, it should return nonzero and copy an error string to ERR
(not exceeding ‘MU_OPT_ERR_MAX’). *Note callback error
indication:: for more information.
Note that if either of the flags ‘MU_OPT_PERMUTE’ or
‘MU_OPT_STOP_AT_ARG’ are used when the option parsing context is created
(*note Option Parsing Flags::), then the successful return value of
‘mu_parse_opts’ will _not_ include the positional arguments parsed
(*note Parsing Options and Environment::). This is so that, after
shifting the arguments by the return value of ‘mu_parse_opts’ with
‘mu_shift_args’, the remaining arguments will be the positional
arguments.
Normally, however, when using an argument callback, you shouldn't
need the return value of ‘mu_parse_opts’ except to check for errors.
If neither of the flags ‘MU_OPT_PERMUTE’ nor ‘MU_OPT_STOP_AT_ARG’ are
given, then the return value of ‘mu_parse_opts’ _will_ include the
positional arguments (i.e., a successful return from ‘mu_parse_opts’
will always return the total number of arguments, options or otherwise).
This is because, if neither ‘MU_OPT_PERMUTE’ nor ‘MU_OPT_STOP_AT_ARG’
are given, it cannot be guaranteed that all positional arguments will
appear after all options. Thus, the return value of ‘mu_parse_opts’
should not be used to shift the arguments, and should only be used to
check for errors.
Here is an example of how to use argument callbacks:
#include <stdio.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x{new,free} */
/* Callbacks to print a message when we find an option or argument. */
static int print_example(void *data, char *err) {
puts("Option found: example");
return 0;
}
static int print_another(void *data, char *err) {
puts("Option found: another");
return 0;
}
static int print_argument(const char *arg, void *data, char *err) {
printf("Argument found: %s\n", arg);
return 0;
}
int main(int argc, char **argv) {
const MU_OPT options[] = {
{
.short_opt = "e",
.long_opt = "example",
.has_arg = MU_OPT_NONE,
.callback_none = print_example
},
{
.short_opt = "a",
.long_opt = "another",
.has_arg = MU_OPT_NONE,
.callback_none = print_another
},
{ 0 }
};
MU_OPT_CONTEXT *context;
int ret;
context = mu_opt_context_xnew(argc, argv, options, 0);
mu_opt_context_set_arg_callback(context, print_argument,
NULL, NULL);
ret = mu_parse_opts(context);
mu_opt_context_xfree(context);
return MU_OPT_ERR(ret);
}
Here is the output of the example program:
$ ./option-ordered-callback foo -e bar --another baz
⊣ Argument found: foo
⊣ Option found: example
⊣ Argument found: bar
⊣ Option found: another
⊣ Argument found: baz
$ ./option-ordered-callback -a foo bar --example
⊣ Option found: another
⊣ Argument found: foo
⊣ Argument found: bar
⊣ Option found: example
Alternatively, you can also determine the order in which options and
positional arguments appear using the ‘MU_OPT_CONTINUE’ flag. If you
use this flag, you should not use the ‘MU_OPT_PERMUTE’ flag (otherwise,
all options will be parsed at once and the ‘MU_OPT_CONTINUE’ flag is
rendered useless). The ‘MU_OPT_STOP_AT_ARG’ is also useless if you use
‘MU_OPT_CONTINUE’, because if you use ‘MU_OPT_STOP_AT_ARG’, you might as
well just parse the options once and then parse the rest of the
arguments, which will only be positional arguments.
Using the ‘MU_OPT_CONTINUE’ flag, you should parse options (maybe
using callbacks if you care about the order of the options themselves),
then parse positional arguments, and then options again until all
arguments are used up. Note, however, that normally you must not call
‘mu_parse_opts’ more than once, unless you pass the ‘MU_OPT_CONTINUE’
flag
All the environment variables will be parsed on the first call of
‘mu_parse_opts’. They will not be parsed again in subsequent calls.
*Note Parsing the Environment:: for more information.
After you parse each non-option argument, you must call
‘mu_opt_context_shift’ on the option context in order to ensure that
‘mu_parse_opts’ will not stop at the argument you just parsed.
-- Function: int mu_opt_context_shift (MU_OPT_CONTEXT *CONTEXT, int
AMOUNT)
Update the internal index of CONTEXT by AMOUNT. AMOUNT may be
negative.
Normally, this function returns zero. However, in the case that
the new index would be less that 1, the new index will instead be
set to 1 and the amount that could not be shifted will be returned.
And in the case that the new index would be greater than or equal
to the number of arguments in CONTEXT, the new index will instead
be set to the number of arguments minus one, and again, the amount
that could not be shifted is returned.
Here is an example illustrating how to parse options and positional
arguments while preserving the order, without using argument callbacks:
#include <stdio.h>
#include <mu/options.h>
#include <mu/safe.h> /* For mu_opt_context_x{new,free} */
/* Callbacks to print a message when we find an option. */
static int print_example(void *data, char *err) {
puts("Option found: example");
return 0;
}
static int print_another(void *data, char *err) {
puts("Option found: another");
return 0;
}
int main(int argc, char **argv) {
const MU_OPT options[] = {
{
.short_opt = "e",
.long_opt = "example",
.has_arg = MU_OPT_NONE,
.callback_none = print_example
},
{
.short_opt = "a",
.long_opt = "another",
.has_arg = MU_OPT_NONE,
.callback_none = print_another
},
{ 0 }
};
MU_OPT_CONTEXT *context;
context = mu_opt_context_xnew(argc, argv, options, MU_OPT_CONTINUE);
while (argc > 1) {
int ret;
/* Parse options. */
ret = mu_parse_opts(context);
if (MU_OPT_ERR(ret))
return 1;
/* Shift the arguments (to get rid of the options we just
parsed). */
mu_shift_args(&argc, &argv, ret);
if (argc > 1) {
/* Print an argument (we don't have to print them all at once
because if `mu_parse_opts' doesn't find any options, it will
just return 0). */
printf("Argument found: %s\n", argv[1]);
/* Shift away this argument. */
mu_shift_args(&argc, &argv, 1);
mu_opt_context_shift(context, 1);
}
}
mu_opt_context_xfree(context);
return 0;
}
The behavior of the above program is identical to the one using
argument callbacks (*note argument callback example::).
2.11 Formatting Help
====================
Many programs have a ‘-h’ or ‘--help’ option which prints out a short
message describing how to use the program. Mu supports automatically
generating a usage message through the use of the ‘help’ and ‘arg_help’
fields of the ‘MU_OPT’ structure (*note Option Structure::).
-- Function: void mu_opt_context_add_help (MU_OPT_CONTEXT *CONTEXT,
const char *USAGE, const char *SHORT_DESCRIPTION, const char
*DESCRIPTION, const char *NOTES, const char *SECTION, const
char *SECTION_NAME, const char *SOURCE, const char *DATE)
Add usage information to CONTEXT. The arguments are as follows:
USAGE
This is a short, human-readable description of the arguments
your program takes. For example, ‘[OPTION]... [FILE]...’. If
USAGE is left ‘NULL’, it will default to ‘[OPTION]...’ if
there is a least one option in OPTIONS or, if OPTIONS is
empty, it will default to ‘’ (the empty string). If you
really want nothing to be printed for USAGE, pass ‘’ (the
empty string) explicitly.
Alternative usages (including no arguments) can be specified,
separated by newlines. For example, if your program is called
‘prog’ and you pass a USAGE of ‘FOO\nBAR\n\nBAZ’ (note the two
‘\n’s after ‘BAR’), the help output will be as follows:
Usage: prog FOO
or: prog BAR
or: prog
or: prog BAZ
[...]
You can think of it as piping USAGE to
sed '1s/^/Usage: prog /; 2,/^/ or: prog /'
(assuming your program is called ‘prog’).
SHORT_DESCRIPTION
This is a very short description (shorter than DESCRIPTION) of
the program. It is used as the description in the NAME
section.
If this parameter is passed as ‘NULL’, a default will be
substituted. This parameter is only used for man page output.
DESCRIPTION
This is a short, human-readable description of whatever your
program does. It is printed right below the USAGE line. It
should be one or two sentences long. For example:
Frobnicate frobs. Nonexistent frobs will be treated as
empty.
You may reference metasyntactic variables specified in USAGE
here (e.g., ‘FILE’) if you like. If you set this to ‘NULL’,
no description will be printed.
Note: you should _not_ write
Mandatory arguments to long options are mandatory for
short options too.
in DESCRIPTION. This will automatically be added to the help
text if it makes sense (i.e., if there exist long options with
required arguments that have short option equivalents).
NOTES
This will be printed at the end of the help message, after the
options. This is where you can put examples, bug report
addresses, etc.
SECTION
The section number of the manual page. This can be any string
(but see SECTION_NAME below), although it should be a number
followed by an optional suffix. The optional suffix can be
something like ncurses uses for its man pages, ‘NCURSES’ (so
the full section would be ‘3NCURSES’). Most likely you should
just set this to a number.
This parameter must not be ‘NULL’, unless man page output is
not being used. This parameter is only used for man page
output.
SECTION_NAME
This is the name of the manual section. For example, ‘User
Commands’.
If this parameter is passed as ‘NULL’, a default will be
chosen based on SECTION. In this case, SECTION must start
with a number between 1 and 9 inclusive except for 7. Section
7 does not have a default name because it is more of a
"miscellaneous" section, and thus you must provide the name
yourself.
This parameter is only used for man page output.
SOURCE
This is the "source" of your program. If your program is part
of a suite, put the name and version of the suite here.
Otherwise, put the name and version of your program here.
If this parameter is passed as ‘NULL’ (not recommended), the
name your program was invoked as will be used. This parameter
is only used for man page output.
DATE
This is the date that the help text was last updated. Update
DATE every time you change the help text for any option, or
you change the name of an option or add a new one. You need
not update this for trivial changes.
The format for DATE is conventionally ‘YYYY-MM-DD’.
If this parameter is passed as ‘NULL’ (not recommended), the
date at which your program was run to generate the man page
will be used instead. Note that the DATE parameter is passed
as ‘NULL’ in the examples for simplicity, but this is still
not recommended.
This parameter is only used for man page output.
-- Function: int mu_opt_context_add_help_options (MU_OPT_CONTEXT
*CONTEXT, int FLAGS)
Add help options to CONTEXT based on FLAGS. If ‘MU_HELP_PREPEND’
is present in FLAGS, the help options will be prepended to the
current options, i.e., inserted before them. Othewise, if
‘MU_HELP_PREPEND’ is not present in FLAGS, the help options will be
appended to the current options, i.e., inserted after them.
FLAGS tells ‘mu_opt_context_add_help_options’ what kind of help
options/environment variables should be created, in addition to
whether it should append or prepend the help options. The
following values may be passed in FLAGS, and can be combined with
‘|’ (bitwise OR).
‘MU_HELP_PREPEND’
This indicates that ‘mu_opt_context_add_help_options’ should
add the help options before the current options, rather than
after. Note that order of the help options themselves is
unchanged.
‘MU_HELP_SHORT’
‘MU_HELP_LONG’
‘MU_HELP_QUESTION_MARK’
These flags tell ‘mu_opt_context_add_help_options’ to create
an option which takes a single optional argument, FORMAT.
‘MU_HELP_SHORT’ will create a short option, ‘-h’, while
‘MU_HELP_LONG’ will create a long option, ‘--help’, and
‘MU_HELP_QUESTION_MARK’ will create a short option, ‘-?’.
FORMAT specifies the output format to use when outputting
help. It can either be ‘man’ to output in a format which can
be parsed by the ‘man’ program, or it can be ‘plain’ or ‘text’
to output in a human-readable, plain-text format.
If FORMAT is omitted, it will default to the value of the
‘MU_HELP_FORMAT’ environment variable if ‘MU_HELP_ENV’ is
passed in FLAGS. Otherwise, if the ‘MU_HELP_FORMAT’
environment variable is not set or does not have a value or
‘MU_HELP_ENV’ was not passed in FLAGS, FORMAT will default to
‘plain’.
*Note:* ‘MU_HELP_QUESTION_MARK’ is not included in
‘MU_HELP_ALL’ (see below). If you want to pass all flags
including ‘MU_HELP_QUESTION_MARK’, you must pass it
explicitly, like so: ‘MU_HELP_ALL | MU_HELP_QUESTION_MARK’.
‘MU_HELP_MAN_SHORT’
‘MU_HELP_MAN_LONG’
These flags tell ‘mu_opt_context_add_help_options’ to create
an option which takes no argument, and always outputs help in
‘man’ format. ‘MU_HELP_MAN_SHORT’ will create a short option,
‘-m’, while ‘MU_HELP_MAN_LONG’ will create a long option,
‘--man’.
‘MU_HELP_ENV’
This flag tells ‘mu_opt_context_add_help_options’ to create an
environment variable, ‘MU_HELP_FORMAT’, which will specify an
output format to use if none was specified to ‘-h’ or
‘--help’. You must only use this flag if ‘MU_HELP_SHORT’ or
‘MU_HELP_LONG’ was also passed in FLAGS.
‘MU_HELP_BOTH’
Equivalent to ‘MU_HELP_SHORT | MU_HELP_LONG’.
‘MU_HELP_MAN_BOTH’
Equivalent to ‘MU_HELP_MAN_SHORT | MU_HELP_MAN_LONG’.
‘MU_HELP_ALL’
Equivalent to passing all flags except for
‘MU_HELP_QUESTION_MARK’, i.e., ‘MU_HELP_BOTH |
MU_HELP_MAN_BOTH | MU_HELP_ENV’.
Output formatted for the ‘man’ program will be piped to ‘man’ if
standard output is a terminal (as determined by ‘isatty’),
otherwise the raw ‘roff’ code will be output to standard output.
If standard output is a terminal but an error occurred while
executing the ‘man’ program, a warning message will be printed and
the raw ‘roff’ code will be output to standard output as if
standard output was not a terminal.
Note: some systems may not provide the necessary functionality to
run the ‘man’ command. In that case, ‘roff’ code will always be
output, regardless of whether standard output is a terminal.
-- Function: int mu_format_help (FILE *STREAM, const MU_OPT_CONTEXT
*CONTEXT)
-- Function: int mu_format_help_man (FILE *STREAM, const MU_OPT_CONTEXT
*CONTEXT)
These functions format a help message, printing it to STREAM. If
you'd like to automatically create a help option that does this,
see ‘mu_opt_context_add_help_options’ above. You might also want
to call these functions manually, for example, if your program
receives no arguments or if ‘mu_parse_opts’ returns an error code
(*note Parsing Options and Environment:: and *note Option Parsing
Errors::).
‘mu_format_help’ will output a human-readable, plain text message,
while ‘mu_format_help_man’ will output ‘roff’ code.
The strings passed to ‘mu_opt_context_add_help’ are used in the
help message, as well as the options in CONTEXT.
-- Function: char * mu_format_help_string (const MU_OPT_CONTEXT
*CONTEXT, unsigned short GOAL, unsigned short WIDTH)
-- Function: char * mu_format_help_man_string (const MU_OPT_CONTEXT
*CONTEXT)
These functions are like ‘mu_format_help’ and ‘mu_format_help_man’
respectively (see above), except that they return the output as a
string rather than printing it. If an error occurs, ‘NULL’ will be
returned and ‘errno’ will be set to indicate the error. If the
returned string is not ‘NULL’, it will by dynamically allocated and
must be freed when you are done with it (*note (libc)Freeing after
Malloc::).
Unlike ‘mu_format_help’, ‘mu_format_help_string’ is unable to
determine the GOAL and WIDTH to use, so you must specify these
parameters yourself. *Note Formatting Text:: for the meanings of
GOAL and WIDTH.
You should provide help text for individual options in the ‘help’ and
‘arg_help’ fields of the ‘MU_OPT’ structure (*note Option Structure::).
‘arg_help’ is similar to the USAGE parameter to ‘mu_format_help’. It
should be a simple string describing the kind of arguments the option
takes. For example, you might write ‘FILE’ if your option takes a file
argument, or ‘WxH’ if it takes a width and height argument, separated by
an ‘x’. If this is left as ‘NULL’, a default will be chosen based on
the type of argument your option takes, specified in the ‘arg_type’
field of the ‘MU_OPT’ structure.
Note: you should _not_ use ‘[’ and ‘]’ in the ‘arg_help’ string. The
‘arg_help’ string will automatically be enclosed in ‘[’ and ‘]’ if the
option takes an optional argument.
‘help’ is a short description of what the option does. Most GNU
utilities use a single sentence, begun with a lowercase letter(1) and
ended without a period. However, you can format ‘help’ however you
like, but keep in mind that it should be fairly short. One sentence or,
if you really must, two.
If the ‘help’ field is left as ‘NULL’, the corresponding option will
remain undocumented as if it did not exist. *Note Option Structure::
for more information.
Below is an example illustrating the usage of both
‘mu_opt_context_add_help_options’ and ‘mu_format_help’. Note that the
‘category’ field is used to denote option categories (*note Option
Structure::).
#include <stdio.h>
#include <stdlib.h>
#include <mu/options.h>
#include <mu/compat.h> /* For __attribute__() */
#include <mu/safe.h> /* For mu_opt_context_x* */
__attribute__((noreturn))
int print_version(void *data, char *err) {
puts("Version 1.0");
exit(0);
}
int main(int argc, char **argv) {
int ret;
const MU_OPT opts_start[] = {
{
.short_opt = "n",
.long_opt = "none",
.has_arg = MU_OPT_NONE,
.help = "an option which takes no argument"
},
{ .category = "Options taking arguments" },
{
.short_opt = "o",
.long_opt = "optional",
.has_arg = MU_OPT_OPTIONAL,
.arg_type = MU_OPT_STRING,
.arg_help = "OPTARG",
.help = "an option which optionally takes an argument"
},
{
.short_opt = "r",
.long_opt = "required",
.has_arg = MU_OPT_REQUIRED,
.arg_type = MU_OPT_STRING,
.arg_help = "REQARG",
.help = "an option which requires an argument"
},
{ .category = "Help options and environment variables" },
{ 0 }
};
/* Options to add after the help options. */
const MU_OPT opts_end[] = {
{ .category = "Version information" },
{
.short_opt = "v",
.long_opt = "version",
.has_arg = MU_OPT_NONE,
.callback_none = print_version,
.help = "print version information and exit"
},
{ 0 }
};
MU_OPT_CONTEXT *context;
context = mu_opt_context_xnew(argc, argv, opts_start,
MU_OPT_BUNDLE | MU_OPT_PERMUTE);
/* Add the help data. */
mu_opt_context_add_help(context, "[OPTION]...", "do stuff",
"Do stuff. If this text is really long, it "
"will be wrapped. Some more text to make "
"this text long enough to be wrapped.",
"Report bugs to <libmu-bug@nongnu.org>.",
"1", NULL, "Mu Examples", NULL);
/* Create the help option. MU_HELP_ALL is equivalent to
MU_HELP_SHORT | MU_HELP_LONG | MU_HELP_MAN_SHORT |
MU_HELP_MAN_LONG | MU_HELP_ENV, so it will create the options
'-h', '--help', '-m', and '--man', and it will create the
environment variable 'MU_HELP_FORMAT'. */
mu_opt_context_xadd_help_options(context, MU_HELP_ALL);
/* Add the other options. */
mu_opt_context_xadd_options(context, opts_end, MU_OPT_APPEND);
/* Parse the options. */
ret = mu_parse_opts(context);
/* If there was an option parsing error, print a usage message so
the user knows how to use us properly. */
if (ret == MU_OPT_ERR_PARSE)
mu_format_help(stderr, context);
mu_opt_context_xfree(context);
return !!MU_OPT_ERR(ret);
}
This is what the output looks like (note, the ‘COLUMNS’ environment
variable is set to 65 so that the output will look good in this manual):
$ COLUMNS=65
$ export COLUMNS
$ ./option-help --help
⊣ Usage: ./option-help [OPTION]...
⊣ Do stuff. If this text is really long, it will be wrapped. Some more text to make this text long
⊣ enough to be wrapped.
⊣
⊣ Mandatory arguments to long options are mandatory for short options too.
⊣ -n, --none an option which takes no argument
⊣
⊣ Options taking arguments:
⊣ -o, --optional[=OPTARG] an option which optionally takes an argument
⊣ -r, --required=REQARG an option which requires an argument
⊣
⊣ Help options and environment variables:
⊣ -h, --help[=plain|man] print this help in plain text format if 'plain', or as a man(1) page
⊣ if 'man'; if the argument is omitted, it will default to the value
⊣ of the MU_HELP_FORMAT environment variable if set, otherwise
⊣ 'plain'.
⊣ -m, --man print this help as a man(1) page
⊣
⊣ Version information:
⊣ -v, --version print version information and exit
⊣
⊣ ENVIRONMENT
⊣
⊣ Help options and environment variables:
⊣ MU_HELP_FORMAT[=plain|man] the default format for -h, --help
⊣
⊣ Report bugs to <libmu-bug@nongnu.org>.
$ ./option-help --foo
error→ ./option-help: '--foo': invalid option
error→ Usage: ./option-help [OPTION]...
error→ Do stuff. If this text is really long, it will be wrapped. Some more text to make this text long
error→ enough to be wrapped.
error→
error→ Mandatory arguments to long options are mandatory for short options too.
error→ -n, --none an option which takes no argument
error→
error→ Options taking arguments:
error→ -o, --optional[=OPTARG] an option which optionally takes an argument
error→ -r, --required=REQARG an option which requires an argument
error→
error→ Help options and environment variables:
error→ -h, --help[=plain|man] print this help in plain text format if 'plain', or as a man(1) page
error→ if 'man'; if the argument is omitted, it will default to the value
error→ of the MU_HELP_FORMAT environment variable if set, otherwise
error→ 'plain'.
error→ -m, --man print this help as a man(1) page
error→
error→ Version information:
error→ -v, --version print version information and exit
error→
error→ ENVIRONMENT
error→
error→ Help options and environment variables:
error→ MU_HELP_FORMAT[=plain|man] the default format for -h, --help
error→
error→ Report bugs to <libmu-bug@nongnu.org>.
---------- Footnotes ----------
(1) Unless it should be uppercase for another reason, for example a
proper noun or acronym.
2.12 Option Parsing Errors
==========================
‘mu_parse_opts’ and ‘mu_parse_subopts’ can fail for several reasons. On
failure, these functions will return an error code depending on the
reason for failure. The error code can be one of the following:
-- Constant: MU_OPT_ERR_PARSE
An option parsing error. This indicates that the user made an
error when specifying options on the command line. You may wish to
print a help message when ‘mu_parse_opts’ returns this value (*note
Formatting Help:: for an example).
-- Constant: MU_OPT_ERR_IO
This indicates that an input/output error occurred while parsing
the arguments. This could indicate, for example, failure to open a
file specified as an argument to an option which has a ‘arg_type’
field of ‘MU_OPT_FILE’ (*note Option Structure::).
-- Constant: MU_OPT_ERR_CALLBACK
This value is returned from ‘mu_parse_opts’ when a callback returns
a nonzero value (*note Option Callbacks::). You can have your
callback set an error flag if you want more details.
-- Macro: int MU_OPT_ERR (int RETVAL)
This macro returns true if RETVAL is one of the above error codes.
3 Formatting Text
*****************
Mu provides several functions for formatting text. The symbols
described below are declared in ‘mu/format.h’.
-- Variable: unsigned short mu_format_tab_stop
The formatting functions always convert ‘TAB’ characters (‘\t’) to
spaces. This global variable specifies the tab stop to be used by
the formatting functions. You may set it directly. The default
value is ‘MU_FORMAT_TAB_STOP’ (see below).
-- Constant: MU_FORMAT_TAB_STOP
The default value for ‘mu_format_tab_stop’ (see above). Equal to
‘8’.
-- Function: int mu_format (FILE *STREAM, unsigned short *CURSOR,
unsigned short GOAL, unsigned short WIDTH, unsigned short
INDENT, unsigned short SUBINDENT, const char *FORMAT, ...)
First, this function creates an internal string based on the
‘printf’-style format string, FORMAT, and a variable number of
extra arguments which are processed according to ‘%’-directives in
FORMAT. *Note (libc)Formatted Output:: for more information on how
FORMAT and the variable arguments are processed.
After this internal string is created, it is then printed to
STREAM, with formatting being done according to the various
parameters. For a description of what these parameters do, see
*note Controlling Formatted Output::.
This function returns ‘0’ on success, or nonzero on error, in which
case ‘errno’ will be set to indicate the error (*note (libc)Error
Reporting::).
-- Function: char * mu_format_string (unsigned short *CURSOR, unsigned
short GOAL, unsigned short WIDTH, unsigned short INDENT,
unsigned short SUBINDENT, const char *FORMAT, ...)
This function is just like ‘mu_format’ (see above), except that it
returns the result in a dynamically allocated string rather than
printing it to a stream.
The return value is the allocated string on success, or ‘NULL’ on
error, in which case ‘errno’ will be set to indicate the error
(*note (libc)Error Reporting::). If this function succeeds, the
returned string must be freed when you are done with it (*note
(libc)Freeing after Malloc::).
-- Function: int mu_vformat (FILE *STREAM, unsigned short *CURSOR,
unsigned short GOAL, unsigned short WIDTH, unsigned short
INDENT, unsigned short SUBINDENT, const char *FORMAT, va_list
AP)
This function is nearly identical to ‘mu_format’, except that it
takes a ‘va_list’ argument, AP, rather than a variable list of
arguments. This is useful if you want to write a variadic function
which calls ‘mu_vformat’ on its arguments (*note (libc)Variadic
Functions::).
-- Function: char * mu_vformat_string (unsigned short *CURSOR, unsigned
short GOAL, unsigned short WIDTH, unsigned short INDENT,
unsigned short SUBINDENT, const char *FORMAT, va_list AP)
This function is nearly identical to ‘mu_format_string’, except
that it takes a ‘va_list’ argument, AP, rather than a variable list
of arguments. See ‘mu_vformat’ above for why this may be useful.
3.1 Controlling Formatted Output
================================
Although the various formatting functions (*note Formatting Text::)
differ slightly in usage, they each take a common set of arguments to
control the formatted output. The meaning of each of these arguments is
described in the table below:
GOAL
This parameter is the “goal†width. Lines will be wrapped at this
width as long as that does not cause words to be split into more
than one line, but will be continued beyond this width if wrapping
would split words into more than one line.
A GOAL of ‘0’ is treated as infinite.
WIDTH
This is the absolute maximum length lines are allowed to be. If a
line is any longer than this, it will be wrapped even if that means
splitting in the middle of a word. If the line _is_ split in the
middle of a word, a ‘-’ will be appended to the end of the line (if
there is room(1)) to indicate that the word is continued on the
next line.
A WIDTH of ‘0’ is treated as infinite.
CURSOR
This is the address of an ‘unsigned short’ which holds the current
column of output text. You should initialize the value whose
address is CURSOR to ‘0’ before calling any of the formatting
functions for the first time with that CURSOR argument. *Note
Formatting Example:: for an example of how this is used.
Note: CURSOR may *not* be ‘NULL’.
INDENT
This specifies the column that the first line of text should be
indented to. If ‘*CURSOR’ is already greater than INDENT, then no
indentation will be performed (i.e., it will be as though ‘indent’
were ‘0’).
Lines following the first one are indented according to SUBINDENT.
SUBINDENT
This is the indentation to use for lines after the first one (see
above). Note that this only applies to a single call of a
formatting function. For example, if you do this:
unsigned short cursor = 0;
mu_format(stdout, 0, 0, &cursor, 10, 5, "foo\n");
mu_format(stdout, 0, 0, &cursor, 10, 5, "bar\n");
both ‘foo’ and ‘bar’ will be indented 10 characters. If you want
‘bar’ to be indented 5 characters, say that explicitly by passing
INDENT as 5 (i.e., ‘mu_format(stdout, 0, 0, &cursor, 5, 5,
"bar\n")’).
---------- Footnotes ----------
(1) There might not be room for a ‘-’ if ‘WIDTH - INDENT’ < 2.
3.2 Formatting Example
======================
Here is an example illustrating the use of ‘mu_format’ and
‘mu_format_string’:
#include <stdio.h>
#include <stdlib.h>
#include <mu/format.h>
int main(void) {
char *str;
unsigned short cursor = 0;
/* Format a message to standard output. */
puts("===== mu_format =====");
mu_format(stdout, &cursor, 40, 50, 4, 2, "\
This is some text. The first line will be indented 4 \
characters, while following lines will be indented 2. Lines \
will be wrapped at 40 characters, except \
reaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaally \
long words, which will be wrapped at 50 characters. A line \
break will appear here:\nno matter what.\n");
/* Write a similarly formatted message to a string. */
str = mu_format_string(&cursor, 40, 50, 4, 2,
"This text is similarly formatted "
"to the text above.\n");
/* Print the string to standard output. */
puts("===== mu_format_string =====");
fputs(str, stdout);
/* We must free the string since `mu_format_string' dynamically
allocates it. */
free(str);
return 0;
}
And here is the output:
$ ./format
⊣ ===== mu_format =====
⊣ This is some text. The first line
⊣ will be indented 4 characters, while
⊣ following lines will be indented 2.
⊣ Lines will be wrapped at 40
⊣ characters, except
⊣ reaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaaa-
⊣ aaaaaaaaaally long words, which will
⊣ be wrapped at 50 characters. A line
⊣ break will appear here:
⊣ no matter what.
⊣ ===== mu_format_string =====
⊣ This text is similarly formatted to
⊣ the text above.
4 Safety Functions
******************
Some functions, like ‘malloc’, rarely fail, and it is often impossible
to recover when these functions do fail. When using these functions, it
may be tempting to simply ignore errors. However, if you do that, it
can cause errors to occur elsewhere, making the source of the error hard
to find.
For example, if you call ‘malloc’ and it returns ‘NULL’, then if you
later try to deference that pointer, it will cause a segmentation fault.
A common solution is to write a function, traditionally called
‘xmalloc’, which calls ‘malloc’ and terminates the program on failure.
However, it can be a pain to write these functions over and over
again, which is why Mu provides them. In addition, the functions
provided in Mu report the exact line in your source where the error
occurred, which might be able to help you find where your program is
using a lot of memory (or where it causes a different type of error to
occur).
In addition, Mu provides several convenience functions for error and
warning reporting.
The functions described in this chapter are declared in ‘mu/safe.h’.
-- Function: void mu_die (int STATUS, const char *FORMAT, ...)
This function prints a formatted error message, specified by
FORMAT, to standard error and exits the program. If STATUS is
negative, ‘mu_die’ will exit the program by calling ‘abort’ (*note
(libc)Aborting a Program::). Otherwise, ‘mu_die’ will pass STATUS
to ‘exit’ (*note (libc)Normal Termination::). STATUS must not be
‘0’.
If the string to be printed, i.e., the expansion of FORMAT, ends in
a newline (‘\n’), the expanded string will be printed verbatim.
Otherwise, if the expanded string does not end in a newline,
context information will be prepended to the string when it is
printed.
If an error occurred while printing the error message, ‘mu_die’
will terminate by calling ‘abort’ regardless of the value of
STATUS.
-- Function: int mu_warn (const char *FORMAT, ...)
This function prints a formatted message to standard error in the
exact same way as ‘mu_die’ specified above, but it returns instead
of calling ‘exit’ or ‘abort’. If ‘mu_warn’ could successfully
print a message to standard error, ‘mu_warn’ will return ‘0’.
Otherwise, ‘mu_warn’ will return a nonzero value.
-- Function: void mu_vdie (int STATUS, const char *FORMAT, va_list AP)
-- Function: int mu_vwarn (const char *FORMAT, va_list AP)
Like ‘mu_die’ and ‘mu_warn’ respectively (see above), except that
these functions take a ‘va_list’ argument, AP, instead of variable
arguments. *Note (libc)Variable Arguments Output::.
-- Function: void * mu_xmalloc (size_t SIZE)
Returns a pointer to dynamically allocated memory of size SIZE.
The returned pointer must be passed to ‘free’. *Note (libc)Basic
Allocation::.
-- Function: void * mu_xcalloc (size_t COUNT, size_t ELTSIZE)
Returns a pointer to dynamically allocated memory of size ‘COUNT *
ELTSIZE’. The returned memory is guaranteed to be initialized to
zero, and this function is also guaranteed to fail safely and
reliably in the event that ‘COUNT * ELTSIZE’ overflows. The
returned pointer must be passed to ‘free’. *Note (libc)Allocating
Cleared Space::.
-- Function: void * mu_xrealloc (void *PTR, size_t NEWSIZE)
Changes the size of the block whose address is PTR to be NEWSIZE.
If the return value is not equal to PTR, PTR will be freed. *Note
(libc)Changing Block Size::.
-- Function: void * mu_xreallocarray (void *PTR, size_t COUNT, size_t
ELTSIZE)
Equivalent to ‘mu_xrealloc(PTR, COUNT * ELTSIZE)’ (see above),
except that this function will fail safely and reliably in the
event that ‘COUNT * ELTSIZE’ overflows. This function is
guaranteed to be available even if your system does not define
‘reallocarray’. *Note (libc)Changing Block Size:: and *note
Compatibility Functions::.
-- Function: char * mu_xstrdup (const char *STRING)
Allocates memory large enough to hold a copy of STRING, and copies
STRING to the newly allocated memory. STRING must be
null-terminated. The returned pointer must be passed to ‘free’.
*Note (libc)Copying Strings and Arrays::.
-- Function: char * mu_xstrndup (const char *STRING, size_t MAX)
Like ‘mu_xstrdup’, but only copies MAX bytes if there was no null
byte in the first MAX bytes of STRING. The returned string will
always be terminated with a null byte. *Note (libc)Truncating
Strings::.
-- Function: unsigned int mu_xasprintf (char **PTR, const char *FORMAT,
...)
Allocates memory large enough to hold the output string, and
returns the allocated string in PTR (which must be passed to
‘free’). Returns the number of characters in ‘*PTR’, not including
the terminating null byte. This function is guaranteed to be
available even if your system does not define ‘asprintf’. *Note
(libc)Dynamic Output:: and *note Compatibility Functions::.
-- Function: unsigned int mu_xvasprintf (char **PTR, const char
*FORMAT, va_list AP)
Like ‘mu_xasprintf’ (see above), but takes a ‘va_list’ argument,
AP, instead of variable arguments. This function is guaranteed to
be available even if your system does not define ‘vasprintf’.
*Note (libc)Variable Arguments Output:: and *note Compatibility
Functions::.
-- Function: void mu_xformat (FILE *STREAM, unsigned short *CURSOR,
unsigned short GOAL, unsigned short WIDTH, unsigned short
INDENT, unsigned short SUBINDENT, const char *FORMAT, ...)
-- Function: char * mu_xformat_string (unsigned short *CURSOR, unsigned
short GOAL, unsigned short WIDTH, unsigned short INDENT,
unsigned short SUBINDENT, const char *FORMAT, ...)
-- Function: void mu_xvformat (FILE *STREAM, unsigned short *CURSOR,
unsigned short GOAL, unsigned short WIDTH, unsigned short
INDENT, unsigned short SUBINDENT, const char *FORMAT, va_list
AP)
-- Function: char * mu_xvformat_string (unsigned short *CURSOR,
unsigned short GOAL, unsigned short WIDTH, unsigned short
INDENT, unsigned short SUBINDENT, const char *FORMAT, va_list
AP)
These functions are like their non-‘x’ counterparts, except that
they terminate the program on error. *Note Formatting Text::.
-- Function: MU_OPT_CONTEXT * mu_opt_context_xnew (int ARGC, char
**ARGV, const MU_OPT *OPTIONS, int FLAGS)
-- Function: MU_OPT_CONTEXT * mu_opt_context_xnew_with_env (int ARGC,
char **ARGV, char **ENVIRONMENT const MU_OPT *OPTIONS, int
FLAGS)
Create a new option parsing context. *Note Parsing Options and
Environment::.
-- Function: MU_SUBOPT_CONTEXT * mu_subopt_context_xnew (const char
*PROG_NAME, const char *SUBOPTSTR, const MU_OPT *SUBOPTS)
Create a new suboption parsing context. *Note Parsing
Suboptions::.
-- Function: void mu_opt_context_xfree (MU_OPT_CONTEXT *CONTEXT)
Free an option parsing context. *Note Parsing Options and
Environment::.
-- Function: void mu_subopt_context_xfree (const MU_SUBOPT_CONTEXT
*CONTEXT)
Free a suboption parsing context. *Note Parsing Suboptions::.
-- Function: void mu_opt_context_xset_no_prefixes (MU_OPT_CONTEXT
*CONTEXT, ...)
-- Function: void mu_opt_context_xset_no_prefix_array (MU_OPT_CONTEXT
*CONTEXT, char **NO_PREFIXES)
-- Function: void mu_subopt_context_xset_no_prefixes (MU_SUBOPT_CONTEXT
*CONTEXT, ...)
-- Function: void mu_subopt_context_xset_no_prefix_array
(MU_SUBOPT_CONTEXT *CONTEXT, char **NO_PREFIXES)
Set alternative negation prefixes for option and suboption parsing
contexts. *Note Negation Prefixes::.
-- Function: void mu_opt_context_xadd_options (MU_OPT_CONTEXT *CONTEXT,
const MU_OPT *OPTIONS, enum MU_OPT_WHERE WHERE)
Add OPTIONS to CONTEXT, either at the beginning or end based on
WHERE. *Note Parsing Options and Environment::.
-- Function: void mu_opt_context_xadd_help_options (MU_OPT_CONTEXT
*CONTEXT, int FLAGS)
Add help options to CONTEXT based on FLAGS. *Note Formatting
Help::.
-- Function: void mu_xformat_help (FILE *STREAM, const MU_OPT_CONTEXT
*CONTEXT)
-- Function: void mu_xformat_help_man (FILE *STREAM, const
MU_OPT_CONTEXT *CONTEXT)
Format a help message from CONTEXT, printing it to STREAM. *Note
Formatting Help::.
-- Function: char * mu_xformat_help_string (const MU_OPT_CONTEXT
*CONTEXT, unsigned short GOAL, unsigned short WIDTH)
-- Function: char * mu_xformat_help_man_string (const MU_OPT_CONTEXT
*CONTEXT)
Format a help message from CONTEXT, returning it as a dynamically
allocated string. *Note Formatting Help::.
5 Compatibility Functions
*************************
Some systems provide useful functions, but you cannot use these without
worrying about your program not being portable to other systems. That
is why Mu provides the functions described below. On systems where
these functions are provided, Mu will use the provided functions. This
is because, in many cases, the functions are hard optimized, and the
alternatives provided by Mu will not be as efficient.
The functions described in this chapter are declared in
‘mu/compat.h’.
The functions described in this chapter are the only symbols not
beginning with ‘mu_’ (or ‘MU_’ for macros). The reason for this is so
that you can simply include ‘mu/compat.h’ in source files where you use
these functions, and it automatically becomes portable (as long as it
doesn't have any other portability issues).
You don't have to worry about defining any feature test macros, such
as ‘_GNU_SOURCE’, although it doesn't hurt to do so. Just make sure you
include ‘mu/compat.h’ *after* any system headers.
All of the functions below set the global variable ‘errno’ on
failure. *Note (libc)Error Reporting::.
-- Function: int asprintf (char **PTR, const char *FORMAT, ...)
This function returns a formatted string in ‘*PTR’ based on the
‘printf’-style format string FORMAT. ‘*PTR’ is dynamically
allocated and must be passed to ‘free’. The return value is the
number of characters in ‘*PTR’ on success, or ‘-1’ on error. *Note
(libc)Dynamic Output::.
-- Function: int vasprintf (char **PTR, const char *FORMAT, va_list AP)
Like ‘asprintf’ (see above), but takes a ‘va_list’ argument, AP,
instead of variable arguments. *Note (libc)Variable Arguments
Output::.
-- Function: char * strchrnul (const char *STRING, int C)
Returns a pointer to the first occurrence of C (converted to a
‘char’) in STRING, or a pointer to the terminating null byte if C
does not occur in STRING. *Note (libc)Search Functions::
-- Function: void * reallocarray (void *PTR, size_t COUNT, ELTSIZE)
Equivalent to ‘realloc(PTR, COUNT * ELTSIZE)’, except that this
function will fail safely and reliably in the event that ‘COUNT *
ELTSIZE’ overflows. *Note (libc)Changing Block Size::.
Appendix A GNU General Public License
*************************************
Version 3, 29 June 2007
Copyright © 2007 Free Software Foundation, Inc. <https://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies of this
license document, but changing it is not allowed.
Preamble
========
The GNU General Public License is a free, copyleft license for software
and other kinds of works.
The licenses for most software and other practical works are designed
to take away your freedom to share and change the works. By contrast,
the GNU General Public License is intended to guarantee your freedom to
share and change all versions of a program--to make sure it remains free
software for all its users. We, the Free Software Foundation, use the
GNU General Public License for most of our software; it applies also to
any other work released this way by its authors. You can apply it to
your programs, too.
When we speak of free software, we are referring to freedom, not
price. Our General Public Licenses are designed to make sure that you
have the freedom to distribute copies of free software (and charge for
them if you wish), that you receive source code or can get it if you
want it, that you can change the software or use pieces of it in new
free programs, and that you know you can do these things.
To protect your rights, we need to prevent others from denying you
these rights or asking you to surrender the rights. Therefore, you have
certain responsibilities if you distribute copies of the software, or if
you modify it: responsibilities to respect the freedom of others.
For example, if you distribute copies of such a program, whether
gratis or for a fee, you must pass on to the recipients the same
freedoms that you received. You must make sure that they, too, receive
or can get the source code. And you must show them these terms so they
know their rights.
Developers that use the GNU GPL protect your rights with two steps:
(1) assert copyright on the software, and (2) offer you this License
giving you legal permission to copy, distribute and/or modify it.
For the developers' and authors' protection, the GPL clearly explains
that there is no warranty for this free software. For both users' and
authors' sake, the GPL requires that modified versions be marked as
changed, so that their problems will not be attributed erroneously to
authors of previous versions.
Some devices are designed to deny users access to install or run
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pattern of such abuse occurs in the area of products for individuals to
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Finally, every program is threatened constantly by software patents.
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The precise terms and conditions for copying, distribution and
modification follow.
TERMS AND CONDITIONS
====================
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this License by making exceptions from one or more of its
conditions. Additional permissions that are applicable to the
entire Program shall be treated as though they were included in
this License, to the extent that they are valid under applicable
law. If additional permissions apply only to part of the Program,
that part may be used separately under those permissions, but the
entire Program remains governed by this License without regard to
the additional permissions.
When you convey a copy of a covered work, you may at your option
remove any additional permissions from that copy, or from any part
of it. (Additional permissions may be written to require their own
removal in certain cases when you modify the work.) You may place
additional permissions on material, added by you to a covered work,
for which you have or can give appropriate copyright permission.
Notwithstanding any other provision of this License, for material
you add to a covered work, you may (if authorized by the copyright
holders of that material) supplement the terms of this License with
terms:
a. Disclaiming warranty or limiting liability differently from
the terms of sections 15 and 16 of this License; or
b. Requiring preservation of specified reasonable legal notices
or author attributions in that material or in the Appropriate
Legal Notices displayed by works containing it; or
c. Prohibiting misrepresentation of the origin of that material,
or requiring that modified versions of such material be marked
in reasonable ways as different from the original version; or
d. Limiting the use for publicity purposes of names of licensors
or authors of the material; or
e. Declining to grant rights under trademark law for use of some
trade names, trademarks, or service marks; or
f. Requiring indemnification of licensors and authors of that
material by anyone who conveys the material (or modified
versions of it) with contractual assumptions of liability to
the recipient, for any liability that these contractual
assumptions directly impose on those licensors and authors.
All other non-permissive additional terms are considered "further
restrictions" within the meaning of section 10. If the Program as
you received it, or any part of it, contains a notice stating that
it is governed by this License along with a term that is a further
restriction, you may remove that term. If a license document
contains a further restriction but permits relicensing or conveying
under this License, you may add to a covered work material governed
by the terms of that license document, provided that the further
restriction does not survive such relicensing or conveying.
If you add terms to a covered work in accord with this section, you
must place, in the relevant source files, a statement of the
additional terms that apply to those files, or a notice indicating
where to find the applicable terms.
Additional terms, permissive or non-permissive, may be stated in
the form of a separately written license, or stated as exceptions;
the above requirements apply either way.
8. Termination.
You may not propagate or modify a covered work except as expressly
provided under this License. Any attempt otherwise to propagate or
modify it is void, and will automatically terminate your rights
under this License (including any patent licenses granted under the
third paragraph of section 11).
However, if you cease all violation of this License, then your
license from a particular copyright holder is reinstated (a)
provisionally, unless and until the copyright holder explicitly and
finally terminates your license, and (b) permanently, if the
copyright holder fails to notify you of the violation by some
reasonable means prior to 60 days after the cessation.
Moreover, your license from a particular copyright holder is
reinstated permanently if the copyright holder notifies you of the
violation by some reasonable means, this is the first time you have
received notice of violation of this License (for any work) from
that copyright holder, and you cure the violation prior to 30 days
after your receipt of the notice.
Termination of your rights under this section does not terminate
the licenses of parties who have received copies or rights from you
under this License. If your rights have been terminated and not
permanently reinstated, you do not qualify to receive new licenses
for the same material under section 10.
9. Acceptance Not Required for Having Copies.
You are not required to accept this License in order to receive or
run a copy of the Program. Ancillary propagation of a covered work
occurring solely as a consequence of using peer-to-peer
transmission to receive a copy likewise does not require
acceptance. However, nothing other than this License grants you
permission to propagate or modify any covered work. These actions
infringe copyright if you do not accept this License. Therefore,
by modifying or propagating a covered work, you indicate your
acceptance of this License to do so.
10. Automatic Licensing of Downstream Recipients.
Each time you convey a covered work, the recipient automatically
receives a license from the original licensors, to run, modify and
propagate that work, subject to this License. You are not
responsible for enforcing compliance by third parties with this
License.
An "entity transaction" is a transaction transferring control of an
organization, or substantially all assets of one, or subdividing an
organization, or merging organizations. If propagation of a
covered work results from an entity transaction, each party to that
transaction who receives a copy of the work also receives whatever
licenses to the work the party's predecessor in interest had or
could give under the previous paragraph, plus a right to possession
of the Corresponding Source of the work from the predecessor in
interest, if the predecessor has it or can get it with reasonable
efforts.
You may not impose any further restrictions on the exercise of the
rights granted or affirmed under this License. For example, you
may not impose a license fee, royalty, or other charge for exercise
of rights granted under this License, and you may not initiate
litigation (including a cross-claim or counterclaim in a lawsuit)
alleging that any patent claim is infringed by making, using,
selling, offering for sale, or importing the Program or any portion
of it.
11. Patents.
A "contributor" is a copyright holder who authorizes use under this
License of the Program or a work on which the Program is based.
The work thus licensed is called the contributor's "contributor
version".
A contributor's "essential patent claims" are all patent claims
owned or controlled by the contributor, whether already acquired or
hereafter acquired, that would be infringed by some manner,
permitted by this License, of making, using, or selling its
contributor version, but do not include claims that would be
infringed only as a consequence of further modification of the
contributor version. For purposes of this definition, "control"
includes the right to grant patent sublicenses in a manner
consistent with the requirements of this License.
Each contributor grants you a non-exclusive, worldwide,
royalty-free patent license under the contributor's essential
patent claims, to make, use, sell, offer for sale, import and
otherwise run, modify and propagate the contents of its contributor
version.
In the following three paragraphs, a "patent license" is any
express agreement or commitment, however denominated, not to
enforce a patent (such as an express permission to practice a
patent or covenant not to sue for patent infringement). To "grant"
such a patent license to a party means to make such an agreement or
commitment not to enforce a patent against the party.
If you convey a covered work, knowingly relying on a patent
license, and the Corresponding Source of the work is not available
for anyone to copy, free of charge and under the terms of this
License, through a publicly available network server or other
readily accessible means, then you must either (1) cause the
Corresponding Source to be so available, or (2) arrange to deprive
yourself of the benefit of the patent license for this particular
work, or (3) arrange, in a manner consistent with the requirements
of this License, to extend the patent license to downstream
recipients. "Knowingly relying" means you have actual knowledge
that, but for the patent license, your conveying the covered work
in a country, or your recipient's use of the covered work in a
country, would infringe one or more identifiable patents in that
country that you have reason to believe are valid.
If, pursuant to or in connection with a single transaction or
arrangement, you convey, or propagate by procuring conveyance of, a
covered work, and grant a patent license to some of the parties
receiving the covered work authorizing them to use, propagate,
modify or convey a specific copy of the covered work, then the
patent license you grant is automatically extended to all
recipients of the covered work and works based on it.
A patent license is "discriminatory" if it does not include within
the scope of its coverage, prohibits the exercise of, or is
conditioned on the non-exercise of one or more of the rights that
are specifically granted under this License. You may not convey a
covered work if you are a party to an arrangement with a third
party that is in the business of distributing software, under which
you make payment to the third party based on the extent of your
activity of conveying the work, and under which the third party
grants, to any of the parties who would receive the covered work
from you, a discriminatory patent license (a) in connection with
copies of the covered work conveyed by you (or copies made from
those copies), or (b) primarily for and in connection with specific
products or compilations that contain the covered work, unless you
entered into that arrangement, or that patent license was granted,
prior to 28 March 2007.
Nothing in this License shall be construed as excluding or limiting
any implied license or other defenses to infringement that may
otherwise be available to you under applicable patent law.
12. No Surrender of Others' Freedom.
If conditions are imposed on you (whether by court order, agreement
or otherwise) that contradict the conditions of this License, they
do not excuse you from the conditions of this License. If you
cannot convey a covered work so as to satisfy simultaneously your
obligations under this License and any other pertinent obligations,
then as a consequence you may not convey it at all. For example,
if you agree to terms that obligate you to collect a royalty for
further conveying from those to whom you convey the Program, the
only way you could satisfy both those terms and this License would
be to refrain entirely from conveying the Program.
13. Use with the GNU Affero General Public License.
Notwithstanding any other provision of this License, you have
permission to link or combine any covered work with a work licensed
under version 3 of the GNU Affero General Public License into a
single combined work, and to convey the resulting work. The terms
of this License will continue to apply to the part which is the
covered work, but the special requirements of the GNU Affero
General Public License, section 13, concerning interaction through
a network will apply to the combination as such.
14. Revised Versions of this License.
The Free Software Foundation may publish revised and/or new
versions of the GNU General Public License from time to time. Such
new versions will be similar in spirit to the present version, but
may differ in detail to address new problems or concerns.
Each version is given a distinguishing version number. If the
Program specifies that a certain numbered version of the GNU
General Public License "or any later version" applies to it, you
have the option of following the terms and conditions either of
that numbered version or of any later version published by the Free
Software Foundation. If the Program does not specify a version
number of the GNU General Public License, you may choose any
version ever published by the Free Software Foundation.
If the Program specifies that a proxy can decide which future
versions of the GNU General Public License can be used, that
proxy's public statement of acceptance of a version permanently
authorizes you to choose that version for the Program.
Later license versions may give you additional or different
permissions. However, no additional obligations are imposed on any
author or copyright holder as a result of your choosing to follow a
later version.
15. Disclaimer of Warranty.
THERE IS NO WARRANTY FOR THE PROGRAM, TO THE EXTENT PERMITTED BY
APPLICABLE LAW. EXCEPT WHEN OTHERWISE STATED IN WRITING THE
COPYRIGHT HOLDERS AND/OR OTHER PARTIES PROVIDE THE PROGRAM "AS IS"
WITHOUT WARRANTY OF ANY KIND, EITHER EXPRESSED OR IMPLIED,
INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE ENTIRE
RISK AS TO THE QUALITY AND PERFORMANCE OF THE PROGRAM IS WITH YOU.
SHOULD THE PROGRAM PROVE DEFECTIVE, YOU ASSUME THE COST OF ALL
NECESSARY SERVICING, REPAIR OR CORRECTION.
16. Limitation of Liability.
IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN
WRITING WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES
AND/OR CONVEYS THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR
DAMAGES, INCLUDING ANY GENERAL, SPECIAL, INCIDENTAL OR
CONSEQUENTIAL DAMAGES ARISING OUT OF THE USE OR INABILITY TO USE
THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF DATA OR DATA
BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD
PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER
PROGRAMS), EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF
THE POSSIBILITY OF SUCH DAMAGES.
17. Interpretation of Sections 15 and 16.
If the disclaimer of warranty and limitation of liability provided
above cannot be given local legal effect according to their terms,
reviewing courts shall apply local law that most closely
approximates an absolute waiver of all civil liability in
connection with the Program, unless a warranty or assumption of
liability accompanies a copy of the Program in return for a fee.
END OF TERMS AND CONDITIONS
===========================
How to Apply These Terms to Your New Programs
=============================================
If you develop a new program, and you want it to be of the greatest
possible use to the public, the best way to achieve this is to make it
free software which everyone can redistribute and change under these
terms.
To do so, attach the following notices to the program. It is safest
to attach them to the start of each source file to most effectively
state the exclusion of warranty; and each file should have at least the
"copyright" line and a pointer to where the full notice is found.
ONE LINE TO GIVE THE PROGRAM'S NAME AND A BRIEF IDEA OF WHAT IT DOES.
Copyright (C) YEAR NAME OF AUTHOR
This program is free software: you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation, either version 3 of the License, or (at
your option) any later version.
This program is distributed in the hope that it will be useful, but
WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
General Public License for more details.
You should have received a copy of the GNU General Public License
along with this program. If not, see <https://www.gnu.org/licenses/>.
Also add information on how to contact you by electronic and paper
mail.
If the program does terminal interaction, make it output a short
notice like this when it starts in an interactive mode:
PROGRAM Copyright (C) YEAR NAME OF AUTHOR
This program comes with ABSOLUTELY NO WARRANTY; for details type ‘show w’.
This is free software, and you are welcome to redistribute it
under certain conditions; type ‘show c’ for details.
The hypothetical commands ‘show w’ and ‘show c’ should show the
appropriate parts of the General Public License. Of course, your
program's commands might be different; for a GUI interface, you would
use an "about box".
You should also get your employer (if you work as a programmer) or
school, if any, to sign a "copyright disclaimer" for the program, if
necessary. For more information on this, and how to apply and follow
the GNU GPL, see <https://www.gnu.org/licenses/>.
The GNU General Public License does not permit incorporating your
program into proprietary programs. If your program is a subroutine
library, you may consider it more useful to permit linking proprietary
applications with the library. If this is what you want to do, use the
GNU Lesser General Public License instead of this License. But first,
please read <https://www.gnu.org/licenses/why-not-lgpl.html>.
Appendix B GNU Free Documentation License
*****************************************
Version 1.3, 3 November 2008
Copyright © 2000, 2001, 2002, 2007, 2008 Free Software Foundation, Inc.
<https://fsf.org/>
Everyone is permitted to copy and distribute verbatim copies
of this license document, but changing it is not allowed.
0. PREAMBLE
The purpose of this License is to make a manual, textbook, or other
functional and useful document “free†in the sense of freedom: to
assure everyone the effective freedom to copy and redistribute it,
with or without modifying it, either commercially or
noncommercially. Secondarily, this License preserves for the
author and publisher a way to get credit for their work, while not
being considered responsible for modifications made by others.
This License is a kind of "copyleft", which means that derivative
works of the document must themselves be free in the same sense.
It complements the GNU General Public License, which is a copyleft
license designed for free software.
We have designed this License in order to use it for manuals for
free software, because free software needs free documentation: a
free program should come with manuals providing the same freedoms
that the software does. But this License is not limited to
software manuals; it can be used for any textual work, regardless
of subject matter or whether it is published as a printed book. We
recommend this License principally for works whose purpose is
instruction or reference.
1. APPLICABILITY AND DEFINITIONS
This License applies to any manual or other work, in any medium,
that contains a notice placed by the copyright holder saying it can
be distributed under the terms of this License. Such a notice
grants a world-wide, royalty-free license, unlimited in duration,
to use that work under the conditions stated herein. The
"Document", below, refers to any such manual or work. Any member
of the public is a licensee, and is addressed as "you". You accept
the license if you copy, modify or distribute the work in a way
requiring permission under copyright law.
A "Modified Version" of the Document means any work containing the
Document or a portion of it, either copied verbatim, or with
modifications and/or translated into another language.
A "Secondary Section" is a named appendix or a front-matter section
of the Document that deals exclusively with the relationship of the
publishers or authors of the Document to the Document's overall
subject (or to related matters) and contains nothing that could
fall directly within that overall subject. (Thus, if the Document
is in part a textbook of mathematics, a Secondary Section may not
explain any mathematics.) The relationship could be a matter of
historical connection with the subject or with related matters, or
of legal, commercial, philosophical, ethical or political position
regarding them.
The "Invariant Sections" are certain Secondary Sections whose
titles are designated, as being those of Invariant Sections, in the
notice that says that the Document is released under this License.
If a section does not fit the above definition of Secondary then it
is not allowed to be designated as Invariant. The Document may
contain zero Invariant Sections. If the Document does not identify
any Invariant Sections then there are none.
The "Cover Texts" are certain short passages of text that are
listed, as Front-Cover Texts or Back-Cover Texts, in the notice
that says that the Document is released under this License. A
Front-Cover Text may be at most 5 words, and a Back-Cover Text may
be at most 25 words.
A "Transparent" copy of the Document means a machine-readable copy,
represented in a format whose specification is available to the
general public, that is suitable for revising the document
straightforwardly with generic text editors or (for images composed
of pixels) generic paint programs or (for drawings) some widely
available drawing editor, and that is suitable for input to text
formatters or for automatic translation to a variety of formats
suitable for input to text formatters. A copy made in an otherwise
Transparent file format whose markup, or absence of markup, has
been arranged to thwart or discourage subsequent modification by
readers is not Transparent. An image format is not Transparent if
used for any substantial amount of text. A copy that is not
"Transparent" is called "Opaque".
Examples of suitable formats for Transparent copies include plain
ASCII without markup, Texinfo input format, LaTeX input format,
SGML or XML using a publicly available DTD, and standard-conforming
simple HTML, PostScript or PDF designed for human modification.
Examples of transparent image formats include PNG, XCF and JPG.
Opaque formats include proprietary formats that can be read and
edited only by proprietary word processors, SGML or XML for which
the DTD and/or processing tools are not generally available, and
the machine-generated HTML, PostScript or PDF produced by some word
processors for output purposes only.
The "Title Page" means, for a printed book, the title page itself,
plus such following pages as are needed to hold, legibly, the
material this License requires to appear in the title page. For
works in formats which do not have any title page as such, "Title
Page" means the text near the most prominent appearance of the
work's title, preceding the beginning of the body of the text.
The "publisher" means any person or entity that distributes copies
of the Document to the public.
A section "Entitled XYZ" means a named subunit of the Document
whose title either is precisely XYZ or contains XYZ in parentheses
following text that translates XYZ in another language. (Here XYZ
stands for a specific section name mentioned below, such as
"Acknowledgements", "Dedications", "Endorsements", or "History".)
To "Preserve the Title" of such a section when you modify the
Document means that it remains a section "Entitled XYZ" according
to this definition.
The Document may include Warranty Disclaimers next to the notice
which states that this License applies to the Document. These
Warranty Disclaimers are considered to be included by reference in
this License, but only as regards disclaiming warranties: any other
implication that these Warranty Disclaimers may have is void and
has no effect on the meaning of this License.
2. VERBATIM COPYING
You may copy and distribute the Document in any medium, either
commercially or noncommercially, provided that this License, the
copyright notices, and the license notice saying this License
applies to the Document are reproduced in all copies, and that you
add no other conditions whatsoever to those of this License. You
may not use technical measures to obstruct or control the reading
or further copying of the copies you make or distribute. However,
you may accept compensation in exchange for copies. If you
distribute a large enough number of copies you must also follow the
conditions in section 3.
You may also lend copies, under the same conditions stated above,
and you may publicly display copies.
3. COPYING IN QUANTITY
If you publish printed copies (or copies in media that commonly
have printed covers) of the Document, numbering more than 100, and
the Document's license notice requires Cover Texts, you must
enclose the copies in covers that carry, clearly and legibly, all
these Cover Texts: Front-Cover Texts on the front cover, and
Back-Cover Texts on the back cover. Both covers must also clearly
and legibly identify you as the publisher of these copies. The
front cover must present the full title with all words of the title
equally prominent and visible. You may add other material on the
covers in addition. Copying with changes limited to the covers, as
long as they preserve the title of the Document and satisfy these
conditions, can be treated as verbatim copying in other respects.
If the required texts for either cover are too voluminous to fit
legibly, you should put the first ones listed (as many as fit
reasonably) on the actual cover, and continue the rest onto
adjacent pages.
If you publish or distribute Opaque copies of the Document
numbering more than 100, you must either include a machine-readable
Transparent copy along with each Opaque copy, or state in or with
each Opaque copy a computer-network location from which the general
network-using public has access to download using public-standard
network protocols a complete Transparent copy of the Document, free
of added material. If you use the latter option, you must take
reasonably prudent steps, when you begin distribution of Opaque
copies in quantity, to ensure that this Transparent copy will
remain thus accessible at the stated location until at least one
year after the last time you distribute an Opaque copy (directly or
through your agents or retailers) of that edition to the public.
It is requested, but not required, that you contact the authors of
the Document well before redistributing any large number of copies,
to give them a chance to provide you with an updated version of the
Document.
4. MODIFICATIONS
You may copy and distribute a Modified Version of the Document
under the conditions of sections 2 and 3 above, provided that you
release the Modified Version under precisely this License, with the
Modified Version filling the role of the Document, thus licensing
distribution and modification of the Modified Version to whoever
possesses a copy of it. In addition, you must do these things in
the Modified Version:
A. Use in the Title Page (and on the covers, if any) a title
distinct from that of the Document, and from those of previous
versions (which should, if there were any, be listed in the
History section of the Document). You may use the same title
as a previous version if the original publisher of that
version gives permission.
B. List on the Title Page, as authors, one or more persons or
entities responsible for authorship of the modifications in
the Modified Version, together with at least five of the
principal authors of the Document (all of its principal
authors, if it has fewer than five), unless they release you
from this requirement.
C. State on the Title page the name of the publisher of the
Modified Version, as the publisher.
D. Preserve all the copyright notices of the Document.
E. Add an appropriate copyright notice for your modifications
adjacent to the other copyright notices.
F. Include, immediately after the copyright notices, a license
notice giving the public permission to use the Modified
Version under the terms of this License, in the form shown in
the Addendum below.
G. Preserve in that license notice the full lists of Invariant
Sections and required Cover Texts given in the Document's
license notice.
H. Include an unaltered copy of this License.
I. Preserve the section Entitled "History", Preserve its Title,
and add to it an item stating at least the title, year, new
authors, and publisher of the Modified Version as given on the
Title Page. If there is no section Entitled "History" in the
Document, create one stating the title, year, authors, and
publisher of the Document as given on its Title Page, then add
an item describing the Modified Version as stated in the
previous sentence.
J. Preserve the network location, if any, given in the Document
for public access to a Transparent copy of the Document, and
likewise the network locations given in the Document for
previous versions it was based on. These may be placed in the
"History" section. You may omit a network location for a work
that was published at least four years before the Document
itself, or if the original publisher of the version it refers
to gives permission.
K. For any section Entitled "Acknowledgements" or "Dedications",
Preserve the Title of the section, and preserve in the section
all the substance and tone of each of the contributor
acknowledgements and/or dedications given therein.
L. Preserve all the Invariant Sections of the Document, unaltered
in their text and in their titles. Section numbers or the
equivalent are not considered part of the section titles.
M. Delete any section Entitled "Endorsements". Such a section
may not be included in the Modified Version.
N. Do not retitle any existing section to be Entitled
"Endorsements" or to conflict in title with any Invariant
Section.
O. Preserve any Warranty Disclaimers.
If the Modified Version includes new front-matter sections or
appendices that qualify as Secondary Sections and contain no
material copied from the Document, you may at your option designate
some or all of these sections as invariant. To do this, add their
titles to the list of Invariant Sections in the Modified Version's
license notice. These titles must be distinct from any other
section titles.
You may add a section Entitled "Endorsements", provided it contains
nothing but endorsements of your Modified Version by various
parties--for example, statements of peer review or that the text
has been approved by an organization as the authoritative
definition of a standard.
You may add a passage of up to five words as a Front-Cover Text,
and a passage of up to 25 words as a Back-Cover Text, to the end of
the list of Cover Texts in the Modified Version. Only one passage
of Front-Cover Text and one of Back-Cover Text may be added by (or
through arrangements made by) any one entity. If the Document
already includes a cover text for the same cover, previously added
by you or by arrangement made by the same entity you are acting on
behalf of, you may not add another; but you may replace the old
one, on explicit permission from the previous publisher that added
the old one.
The author(s) and publisher(s) of the Document do not by this
License give permission to use their names for publicity for or to
assert or imply endorsement of any Modified Version.
5. COMBINING DOCUMENTS
You may combine the Document with other documents released under
this License, under the terms defined in section 4 above for
modified versions, provided that you include in the combination all
of the Invariant Sections of all of the original documents,
unmodified, and list them all as Invariant Sections of your
combined work in its license notice, and that you preserve all
their Warranty Disclaimers.
The combined work need only contain one copy of this License, and
multiple identical Invariant Sections may be replaced with a single
copy. If there are multiple Invariant Sections with the same name
but different contents, make the title of each such section unique
by adding at the end of it, in parentheses, the name of the
original author or publisher of that section if known, or else a
unique number. Make the same adjustment to the section titles in
the list of Invariant Sections in the license notice of the
combined work.
In the combination, you must combine any sections Entitled
"History" in the various original documents, forming one section
Entitled "History"; likewise combine any sections Entitled
"Acknowledgements", and any sections Entitled "Dedications". You
must delete all sections Entitled "Endorsements."
6. COLLECTIONS OF DOCUMENTS
You may make a collection consisting of the Document and other
documents released under this License, and replace the individual
copies of this License in the various documents with a single copy
that is included in the collection, provided that you follow the
rules of this License for verbatim copying of each of the documents
in all other respects.
You may extract a single document from such a collection, and
distribute it individually under this License, provided you insert
a copy of this License into the extracted document, and follow this
License in all other respects regarding verbatim copying of that
document.
7. AGGREGATION WITH INDEPENDENT WORKS
A compilation of the Document or its derivatives with other
separate and independent documents or works, in or on a volume of a
storage or distribution medium, is called an "aggregate" if the
copyright resulting from the compilation is not used to limit the
legal rights of the compilation's users beyond what the individual
works permit. When the Document is included in an aggregate, this
License does not apply to the other works in the aggregate which
are not themselves derivative works of the Document.
If the Cover Text requirement of section 3 is applicable to these
copies of the Document, then if the Document is less than one half
of the entire aggregate, the Document's Cover Texts may be placed
on covers that bracket the Document within the aggregate, or the
electronic equivalent of covers if the Document is in electronic
form. Otherwise they must appear on printed covers that bracket
the whole aggregate.
8. TRANSLATION
Translation is considered a kind of modification, so you may
distribute translations of the Document under the terms of section
4. Replacing Invariant Sections with translations requires special
permission from their copyright holders, but you may include
translations of some or all Invariant Sections in addition to the
original versions of these Invariant Sections. You may include a
translation of this License, and all the license notices in the
Document, and any Warranty Disclaimers, provided that you also
include the original English version of this License and the
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Appendix C Concept Index
************************
* Menu:
* aliases for environment variables: Option Aliases. (line 626)
* aliases for options: Option Aliases. (line 626)
* alternative negation prefixes: Negation Prefixes. (line 768)
* argument callback example: Ordered Option Parsing.
(line 2089)
* argument callback example, output: Ordered Option Parsing.
(line 2139)
* argument types, to options: Option Argument Types.
(line 942)
* arguments, boolean, to options: Option Argument Types.
(line 962)
* arguments, directory, to options: Option Argument Types.
(line 1047)
* arguments, enumerated, parsing: Parsing Enums. (line 1359)
* arguments, enumerated, to options: Option Argument Types.
(line 1062)
* arguments, file, to options: Option Argument Types.
(line 1019)
* arguments, floating-point, to options: Option Argument Types.
(line 993)
* arguments, integer, to options: Option Argument Types.
(line 977)
* arguments, none, to options: Option Arguments. (line 872)
* arguments, optional, to options: Option Arguments. (line 883)
* arguments, required, to options: Option Arguments. (line 915)
* arguments, stream, to options: Option Argument Types.
(line 1019)
* arguments, string, to options: Option Argument Types.
(line 1012)
* arguments, suboption, to options: Option Argument Types.
(line 1068)
* arguments, to options: Option Arguments. (line 862)
* arguments, to options, optional: Option Arguments. (line 862)
* arguments, to options, required: Option Arguments. (line 862)
* bindings: Using Mu. (line 99)
* boolean arguments to options: Option Argument Types.
(line 962)
* bugs, reporting: Reporting Bugs. (line 121)
* C programming language: Using Mu. (line 99)
* callback data, freeing: Option Callbacks. (line 1151)
* callback example: Option Callbacks. (line 1254)
* callback example, output: Option Callbacks. (line 1339)
* callbacks, directories: Option Callbacks. (line 1159)
* callbacks, files: Option Callbacks. (line 1159)
* callbacks, indicating error: Option Callbacks. (line 1241)
* callbacks, option parsing: Option Callbacks. (line 1076)
* callbacks, option, negatable, why not: Negatable Options. (line 695)
* callbacks, ordering: Option Callbacks. (line 1127)
* codes, error, option parsing: Option Parsing Errors.
(line 2686)
* command line options, parsing: Parsing Options and Environment.
(line 149)
* compatibility functions: Compatibility Functions.
(line 3082)
* data, callback, freeing: Option Callbacks. (line 1151)
* declaration, before definition: Parsing Options and Environment.
(line 175)
* declaration, before definition, example: Parsing Options and Environment.
(line 180)
* declaration, before setting: Parsing Options and Environment.
(line 175)
* declaration, before setting, example: Parsing Options and Environment.
(line 180)
* defining after declaration: Parsing Options and Environment.
(line 175)
* defining after declaration, example: Parsing Options and Environment.
(line 180)
* designated initializers: Parsing Options and Environment.
(line 159)
* designated initializers, example: Parsing Options and Environment.
(line 166)
* die: Safety Functions. (line 2919)
* directories in callbacks: Option Callbacks. (line 1159)
* directory arguments to options: Option Argument Types.
(line 1047)
* dying: Safety Functions. (line 2919)
* enumerated arguments to options: Option Argument Types.
(line 1062)
* enumerated arguments, parsing: Parsing Enums. (line 1359)
* environment variable negation, not allowed: Negatable Options.
(line 670)
* environment variable parsing example: Parsing the Environment.
(line 1766)
* environment variable parsing example, output: Parsing the Environment.
(line 1856)
* environment variable, MU_HELP_FORMAT: Formatting Help. (line 2380)
* environment variables, aliases: Option Aliases. (line 626)
* environment, parsing: Parsing the Environment.
(line 1712)
* error codes, option parsing: Option Parsing Errors.
(line 2686)
* error reporting: Safety Functions. (line 2919)
* example of declaration, before definition: Parsing Options and Environment.
(line 180)
* example of declaration, before setting: Parsing Options and Environment.
(line 180)
* example of defining after declaration: Parsing Options and Environment.
(line 180)
* example of designated initializers: Parsing Options and Environment.
(line 166)
* example of initializers, designated: Parsing Options and Environment.
(line 166)
* example of setting after declaration: Parsing Options and Environment.
(line 180)
* example, argument callback: Ordered Option Parsing.
(line 2089)
* example, argument callback, output: Ordered Option Parsing.
(line 2139)
* example, callback: Option Callbacks. (line 1254)
* example, callback, output: Option Callbacks. (line 1339)
* example, environment variable parsing: Parsing the Environment.
(line 1766)
* example, environment variable parsing, output: Parsing the Environment.
(line 1856)
* example, formatting text: Formatting Example. (line 2838)
* example, formatting text, output: Formatting Example. (line 2877)
* example, help option: Formatting Help. (line 2523)
* example, help option, output: Formatting Help. (line 2618)
* example, option parsing, ordered: Ordered Option Parsing.
(line 2089)
* example, option parsing, ordered, output: Ordered Option Parsing.
(line 2139)
* example, option parsing, ordered, without argument callbacks: Ordered Option Parsing.
(line 2191)
* example, option, help: Formatting Help. (line 2523)
* example, option, help, output: Formatting Help. (line 2618)
* example, suboption parsing: Parsing Suboptions. (line 1601)
* example, suboption parsing, output: Parsing Suboptions. (line 1687)
* example, text, formatting: Formatting Example. (line 2838)
* example, text, formatting, output: Formatting Example. (line 2877)
* file arguments to options: Option Argument Types.
(line 1019)
* files in callbacks: Option Callbacks. (line 1159)
* flags, option parsing: Option Parsing Flags.
(line 1896)
* floating-point arguments to options: Option Argument Types.
(line 993)
* following lines, indenting: Controlling Formatted Output.
(line 2817)
* formatting help: Formatting Help. (line 2259)
* formatting text: Formatting Text. (line 2713)
* formatting text example: Formatting Example. (line 2838)
* formatting text example, output: Formatting Example. (line 2877)
* formatting usage message: Formatting Help. (line 2259)
* formatting, help message: Formatting Help. (line 2463)
* formatting, man page: Formatting Help. (line 2463)
* formatting, usage message: Formatting Help. (line 2463)
* freeing callback data: Option Callbacks. (line 1151)
* functions, compatibility: Compatibility Functions.
(line 3082)
* functions, safety: Safety Functions. (line 2896)
* hard wrapping lines: Controlling Formatted Output.
(line 2790)
* headers, including: Using Mu. (line 102)
* help message formatting: Formatting Help. (line 2463)
* help option: Formatting Help. (line 2380)
* help option example: Formatting Help. (line 2523)
* help option example, output: Formatting Help. (line 2618)
* help, formatting: Formatting Help. (line 2259)
* inclusion of headers: Using Mu. (line 102)
* indenting following lines: Controlling Formatted Output.
(line 2817)
* indenting text: Controlling Formatted Output.
(line 2809)
* indicating error in callbacks: Option Callbacks. (line 1241)
* initializers, designated: Parsing Options and Environment.
(line 159)
* initializers, designated, example: Parsing Options and Environment.
(line 166)
* integer arguments to options: Option Argument Types.
(line 977)
* language, programming, C: Using Mu. (line 99)
* languages, programming, other: Using Mu. (line 99)
* lines, following, indenting: Controlling Formatted Output.
(line 2817)
* lines, hard wrapping: Controlling Formatted Output.
(line 2790)
* lines, long, wrapping: Controlling Formatted Output.
(line 2782)
* linking: Using Mu. (line 107)
* long lines, wrapping: Controlling Formatted Output.
(line 2782)
* man option: Formatting Help. (line 2380)
* man page formatting: Formatting Help. (line 2463)
* MU_HELP_FORMAT environment variable: Formatting Help. (line 2380)
* negatable option callbacks, why not: Negatable Options. (line 695)
* negatable options: Negatable Options. (line 653)
* negation prefixes, alternative: Negation Prefixes. (line 768)
* negation, of environment variables, not allowed: Negatable Options.
(line 670)
* no argument to options: Option Arguments. (line 872)
* notation used in this manual: Terms and Notation. (line 79)
* option argument types: Option Argument Types.
(line 942)
* option arguments: Option Arguments. (line 862)
* option callbacks, negatable, why not: Negatable Options. (line 695)
* option parsing callbacks: Option Callbacks. (line 1076)
* option parsing error codes: Option Parsing Errors.
(line 2686)
* option parsing flags: Option Parsing Flags.
(line 1896)
* option parsing, ordered: Ordered Option Parsing.
(line 2034)
* option precedence: Option Parsing Flags.
(line 1930)
* option structure: Option Structure. (line 331)
* option, help: Formatting Help. (line 2380)
* option, help, example: Formatting Help. (line 2523)
* option, help, example, output: Formatting Help. (line 2618)
* option, man: Formatting Help. (line 2380)
* optional arguments to options: Option Arguments. (line 883)
* options with optional arguments: Option Arguments. (line 883)
* options with required arguments: Option Arguments. (line 915)
* options without arguments: Option Arguments. (line 872)
* options, aliases: Option Aliases. (line 626)
* options, command line, parsing: Parsing Options and Environment.
(line 149)
* options, negatable: Negatable Options. (line 653)
* order in which callbacks are called: Option Callbacks. (line 1127)
* ordered option parsing: Ordered Option Parsing.
(line 2034)
* ordered option parsing example: Ordered Option Parsing.
(line 2089)
* ordered option parsing example, output: Ordered Option Parsing.
(line 2139)
* ordered option parsing example, without argument callbacks: Ordered Option Parsing.
(line 2191)
* other programming languages: Using Mu. (line 99)
* parsing command line options: Parsing Options and Environment.
(line 149)
* parsing enumerated arguments: Parsing Enums. (line 1359)
* parsing environment: Parsing the Environment.
(line 1712)
* parsing suboptions: Parsing Suboptions. (line 1512)
* precedence, of options: Option Parsing Flags.
(line 1930)
* prefixes, negation, alternative: Negation Prefixes. (line 768)
* programming language, C: Using Mu. (line 99)
* programming languages, other: Using Mu. (line 99)
* reporting bugs: Reporting Bugs. (line 121)
* reporting errors: Safety Functions. (line 2919)
* reporting warnings: Safety Functions. (line 2937)
* required arguments to options: Option Arguments. (line 915)
* safety functions: Safety Functions. (line 2896)
* setting after declaration: Parsing Options and Environment.
(line 175)
* setting after declaration, example: Parsing Options and Environment.
(line 180)
* stream arguments to options: Option Argument Types.
(line 1019)
* string arguments to options: Option Argument Types.
(line 1012)
* structure, of options: Option Structure. (line 331)
* suboption arguments to options: Option Argument Types.
(line 1068)
* suboption parsing example: Parsing Suboptions. (line 1601)
* suboption parsing example, output: Parsing Suboptions. (line 1687)
* suboptions, parsing: Parsing Suboptions. (line 1512)
* terms used in this manual: Terms and Notation. (line 79)
* text, formatting: Formatting Text. (line 2713)
* text, formatting, example: Formatting Example. (line 2838)
* text, formatting, example, output: Formatting Example. (line 2877)
* text, indenting: Controlling Formatted Output.
(line 2809)
* types of arguments to options: Option Argument Types.
(line 942)
* usage message formatting: Formatting Help. (line 2463)
* usage message, formatting: Formatting Help. (line 2259)
* variable, environment, parsing example: Parsing the Environment.
(line 1766)
* variable, environment, parsing example, output: Parsing the Environment.
(line 1856)
* warning: Safety Functions. (line 2937)
* why not negatable option callbacks: Negatable Options. (line 695)
* wrapping long lines: Controlling Formatted Output.
(line 2782)
* wrapping, lines, hard: Controlling Formatted Output.
(line 2790)
Appendix D Function and Macro Index
***********************************
* Menu:
* asprintf: Compatibility Functions.
(line 3105)
* mu_die: Safety Functions. (line 2919)
* mu_format: Formatting Text. (line 2726)
* mu_format_help: Formatting Help. (line 2463)
* mu_format_help_man: Formatting Help. (line 2465)
* mu_format_help_man_string: Formatting Help. (line 2483)
* mu_format_help_string: Formatting Help. (line 2481)
* mu_format_string: Formatting Text. (line 2744)
* mu_opt_context_add_help: Formatting Help. (line 2264)
* mu_opt_context_add_help_options: Formatting Help. (line 2380)
* mu_opt_context_add_options: Parsing Options and Environment.
(line 299)
* mu_opt_context_free: Parsing Options and Environment.
(line 251)
* mu_opt_context_new: Parsing Options and Environment.
(line 194)
* mu_opt_context_new_with_env: Parsing Options and Environment.
(line 196)
* mu_opt_context_set_arg_callback: Ordered Option Parsing.
(line 2046)
* mu_opt_context_set_no_prefix_array: Negation Prefixes. (line 780)
* mu_opt_context_set_no_prefixes: Negation Prefixes. (line 778)
* mu_opt_context_shift: Ordered Option Parsing.
(line 2175)
* mu_opt_context_xadd_help_options: Safety Functions. (line 3060)
* mu_opt_context_xadd_options: Safety Functions. (line 3055)
* mu_opt_context_xfree: Safety Functions. (line 3036)
* mu_opt_context_xnew: Safety Functions. (line 3023)
* mu_opt_context_xnew_with_env: Safety Functions. (line 3025)
* mu_opt_context_xset_no_prefix_array: Safety Functions. (line 3046)
* mu_opt_context_xset_no_prefixes: Safety Functions. (line 3044)
* MU_OPT_ERR: Option Parsing Errors.
(line 2707)
* mu_parse_opts: Parsing Options and Environment.
(line 262)
* mu_parse_subopts: Parsing Suboptions. (line 1591)
* mu_shift_args: Parsing Options and Environment.
(line 313)
* mu_subopt_context_free: Parsing Suboptions. (line 1583)
* mu_subopt_context_new: Parsing Suboptions. (line 1569)
* mu_subopt_context_set_no_prefix_array: Negation Prefixes. (line 784)
* mu_subopt_context_set_no_prefixes: Negation Prefixes. (line 782)
* mu_subopt_context_xfree: Safety Functions. (line 3040)
* mu_subopt_context_xnew: Safety Functions. (line 3031)
* mu_subopt_context_xset_no_prefix_array: Safety Functions. (line 3050)
* mu_subopt_context_xset_no_prefixes: Safety Functions. (line 3048)
* mu_vdie: Safety Functions. (line 2944)
* mu_vformat: Formatting Text. (line 2757)
* mu_vformat_string: Formatting Text. (line 2767)
* mu_vwarn: Safety Functions. (line 2945)
* mu_warn: Safety Functions. (line 2937)
* mu_xasprintf: Safety Functions. (line 2989)
* mu_xcalloc: Safety Functions. (line 2955)
* mu_xformat: Safety Functions. (line 3006)
* mu_xformat_help: Safety Functions. (line 3065)
* mu_xformat_help_man: Safety Functions. (line 3067)
* mu_xformat_help_man_string: Safety Functions. (line 3074)
* mu_xformat_help_string: Safety Functions. (line 3072)
* mu_xformat_string: Safety Functions. (line 3009)
* mu_xmalloc: Safety Functions. (line 2950)
* mu_xrealloc: Safety Functions. (line 2963)
* mu_xreallocarray: Safety Functions. (line 2968)
* mu_xstrdup: Safety Functions. (line 2977)
* mu_xstrndup: Safety Functions. (line 2983)
* mu_xvasprintf: Safety Functions. (line 2998)
* mu_xvformat: Safety Functions. (line 3012)
* mu_xvformat_string: Safety Functions. (line 3016)
* reallocarray: Compatibility Functions.
(line 3122)
* strchrnul: Compatibility Functions.
(line 3117)
* vasprintf: Compatibility Functions.
(line 3112)
Appendix E Type Index
*********************
* Menu:
* enum: Parsing Options and Environment.
(line 286)
* enum MU_OPT_ARG_TYPE: Option Argument Types.
(line 960)
* enum MU_OPT_HAS_ARG: Option Arguments. (line 870)
* MU_ENUM_VALUE: Parsing Enums. (line 1379)
* MU_OPT: Option Structure. (line 331)
* MU_OPT_CONTEXT: Parsing Options and Environment.
(line 188)
* MU_SUBOPT_CONTEXT: Parsing Suboptions. (line 1564)
Appendix F Variable and Constant Index
**************************************
* Menu:
* mu_format_tab_stop: Formatting Text. (line 2716)
* MU_FORMAT_TAB_STOP: Formatting Text. (line 2722)
* MU_HELP_ALL: Formatting Help. (line 2446)
* MU_HELP_BOTH: Formatting Help. (line 2440)
* MU_HELP_ENV: Formatting Help. (line 2433)
* MU_HELP_LONG: Formatting Help. (line 2401)
* MU_HELP_MAN_BOTH: Formatting Help. (line 2443)
* MU_HELP_MAN_LONG: Formatting Help. (line 2426)
* MU_HELP_MAN_SHORT: Formatting Help. (line 2425)
* MU_HELP_PREPEND: Formatting Help. (line 2394)
* MU_HELP_QUESTION_MARK: Formatting Help. (line 2402)
* MU_HELP_SHORT: Formatting Help. (line 2400)
* MU_OPT_ALLOW_INVALID: Option Parsing Flags.
(line 1985)
* MU_OPT_BUNDLE: Option Parsing Flags.
(line 1920)
* MU_OPT_CONTINUE: Option Parsing Flags.
(line 1970)
* MU_OPT_ERR_CALLBACK: Option Parsing Errors.
(line 2702)
* MU_OPT_ERR_IO: Option Parsing Errors.
(line 2696)
* MU_OPT_ERR_MAX: Option Callbacks. (line 1241)
* MU_OPT_ERR_PARSE: Option Parsing Errors.
(line 2690)
* MU_OPT_IGNORE_POSIX: Option Parsing Flags.
(line 2003)
* MU_OPT_PERMUTE: Option Parsing Flags.
(line 1900)
* MU_OPT_STOP_AT_ARG: Option Parsing Flags.
(line 2010)