timespec_get(3)		    Library Functions Manual		 timespec_get(3)

NAME
     timespec_get, timespec_getres - ISO C interface to clock and time functions

LIBRARY
     Standard C library (libc, -lc)

SYNOPSIS
     #include <time.h>

     int timespec_get(struct timespec *res, int base);
     int timespec_getres(struct timespec *tp, int base);

 Feature Test Macro Requirements for glibc (see feature_test_macros(7)):

     timespec_get(), TIME_UTC:
	 _ISOC11_SOURCE

     timespec_getres(), TIME_MONOTONIC, TIME_ACTIVE, TIME_THREAD_ACTIVE:
	 _ISOC23_SOURCE

DESCRIPTION
     The timespec_get() function stores the current time, based on the specified
     time base, in the timespec(3type) structure pointed to by res.

     The  timespec_getres() function stores the resolution of times retrieved by
     timespec_get() with the specified time base in the	 timespec(3type)  struc-
     ture  pointed to by tp, if tp is non-NULL.	 For a particular time base, the
     resolution is constant for the lifetime of the calling process.

     The time base base is one of the following:

     TIME_UTC
	    A system-wide time base that measures real (i.e., wall-clock)  time.
	    The	 time and resolution in this time base are the same as those re-
	    trieved  by	  clock_gettime(CLOCK_REALTIME,	  res)	 and   clock_ge-
	    tres(CLOCK_REALTIME, tp), respectively.

     TIME_MONOTONIC
	    A  time  base  that	 measures time since an unspecified point in the
	    past, where the time within a process will not decrease even if  the
	    system's  real  time clock is set or adjusted.  The time and resolu-
	    tion in this time base are the same as those retrieved by clock_get-
	    time(CLOCK_MONOTONIC, res)	and  clock_getres(CLOCK_MONOTONIC,  tp),
	    respectively.

     TIME_ACTIVE
	    A  process-specific time base that measures CPU time consumed by the
	    calling process.  The time and resolution in this time base are  the
	    same	as	 those	     retrieved	     by	      clock_get-
	    time(CLOCK_PROCESS_CPUTIME_ID,	 res)	    and	       clock_ge-
	    tres(CLOCK_PROCESS_CPUTIME_ID, tp), respectively.

     TIME_THREAD_ACTIVE
	    A  thread-specific	time base that measures CPU time consumed by the
	    calling thread.  The time and resolution in this time base	are  the
	    same	as	 those	     retrieved	     by	      clock_get-
	    time(CLOCK_THREAD_CPUTIME_ID,	res)	    and	       clock_ge-
	    tres(CLOCK_THREAD_CPUTIME_ID, tp), respectively.

RETURN VALUE
     timespec_get()  returns the nonzero base if it is a supported time base and
     the current time was successfully retrieved, or 0 otherwise.

     timespec_getres() returns the nonzero base if it is a supported time  base,
     or 0 otherwise.

ATTRIBUTES
     For  an  explanation  of the terms used in this section, see attributes(7).
     allbox; lbx lb lb l l l.  Interface Attribute Value T{ timespec_get(),
     timespec_getres() T}   Thread safety  MT-Safe

STANDARDS
     timespec_get()
	    C23, POSIX.1-2024.
     TIME_UTC
	    C23 (though ISO C doesn't specify the time epoch), POSIX.1-2024.

     timespec_getres()
     TIME_MONOTONIC
     TIME_ACTIVE
     TIME_THREAD_ACTIVE
	    C23.

HISTORY
     timespec_get()
     TIME_UTC
	    C11, POSIX.1-2024, glibc 2.16, musl 1.1.10.

     timespec_getres()
	    C23, glibc 2.34.

     TIME_MONOTONIC
     TIME_ACTIVE
     TIME_THREAD_ACTIVE
	    C23, glibc 2.43.

SEE ALSO
     clock_gettime(2), clock_getres(2)

Linux man-pages 6.18		   2026-02-11			 timespec_get(3)