.\"	$OpenBSD: clock_getcpuclockid.3,v 1.3 2015/01/15 19:26:27 schwarze Exp $
.\"
.\" Copyright (c) 2013 Philip Guenther <guenther@openbsd.org>
.\"
.\" Permission to use, copy, modify, and distribute this software for any
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.\" copyright notice and this permission notice appear in all copies.
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.\"
.Dd $Mdocdate: January 15 2015 $
.Dt CLOCK_GETCPUCLOCKID 3
.Os
.Sh NAME
.Nm clock_getcpuclockid
.Nd get a clock measuring process CPU time
.Sh SYNOPSIS
.In time.h
.Ft int
.Fn clock_getcpuclockid "pid_t pid" "clockid_t *clock_id"
.Sh DESCRIPTION
The
.Fn clock_getcpuclockid
function allows the calling process to get a
.Vt clockid_t
value that measures the time spent by CPUs running in user or kernel mode
on behalf of the process specified by
.Fa pid .
If
.Fa pid
is zero, then a clock for the calling process will be returned.
.Sh RETURN VALUES
If successful,
.Fn clock_getcpuclockid
will return zero.
Otherwise an error number will be returned to indicate the error.
.Sh ERRORS
.Fn clock_getcpuclockid
will fail if:
.Bl -tag -width Er
.It Bq Er EPERM
.Fa pid
is neither zero nor the PID of the calling process.
.El
.Sh SEE ALSO
.Xr clock_gettime 2 ,
.Xr pthread_getcpuclockid 3
.Sh STANDARDS
The
.Fn clock_getcpuclockid
function conforms to
.St -p1003.1-2008 .
.Sh HISTORY
The
.Fn clock_getcpuclockid
function first appeared in IEEE Std 1003.1d-1999
.Pq Dq POSIX.1d
and has been available since
.Ox 5.4 .