---

1.3.2 Predefined Clocks

The clock type controls the type of measurement performed by a chronometer or a timer. The library implements the following clock type definitions (see Time Reference) if they were available at build time:

• realtime:

  Wall clock time provided by the operating system. CLOCK_TAI is preferred when it is availableto CLOCK_REALTIME.

• monotonic:

  Non decreasing clock time, such as CLOCK_MONOTONIC.

• process:

  Process time, such as CLOCK_PROCESS_CPUTIME_ID.

• thread:

  Execution thread time.