This function can be called to obtain the resolution of the system
clock. The resolution is expressed as the time difference (quantum)
corresponding to the smallest increment the clock may make, in
nanoseconds, and returned in the
timespec pointed to by
Due to rounding errors in calculations, and the possibly of a fine
adjustment being in progress
is enabled), it is not guaranteed that the difference between two
sequential reads of system time will never be smaller than the
resolution returned here.
This function returns a standard error code, as defined in <errno.h>, or ENOERR on success.