Description

   The clock_getres function obtains the resolution value for the
   specified clock. Clock resolutions are implementation-dependent
   and cannot be set by a process.

   If the res argument is not NULL, the resolution of the specified
   clock is stored in the location pointed to by res.

   If res is NULL, the clock resolution is not stored.

   If the time argument (tp) of clock_settime is not a multiple of
   res, then the value is truncated to a multiple of res.

   On success, the function returns 0.

   On failure, the function returns -1 and sets errno to indicate
   the error.

   See also clock_gettime, clock_settime, time, and ctime.