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.\" Hey Emacs! This file is -*- nroff -*- source.
.\"
.\" Copyright (c) 1992 Drew Eckhardt, March 28, 1992
.\" and Copyright (c) 2002 Michael Kerrisk
.\"
.\" Permission is granted to make and distribute verbatim copies of this
.\" manual provided the copyright notice and this permission notice are
.\" preserved on all copies.
.\"
.\" Permission is granted to copy and distribute modified versions of this
.\" manual under the conditions for verbatim copying, provided that the
.\" entire resulting derived work is distributed under the terms of a
.\" permission notice identical to this one.
.\"
.\" Since the Linux kernel and libraries are constantly changing, this
.\" manual page may be incorrect or out-of-date. The author(s) assume no
.\" responsibility for errors or omissions, or for damages resulting from
.\" the use of the information contained herein. The author(s) may not
.\" have taken the same level of care in the production of this manual,
.\" which is licensed free of charge, as they might when working
.\" professionally.
.\"
.\" Formatted or processed versions of this manual, if unaccompanied by
.\" the source, must acknowledge the copyright and authors of this work.
.\"
.\" 2004-11-16 -- mtk: the getrlimit.2 page, which formerly included
.\" coverage of getrusage(2), has been split, so that the latter is
.\" now covered in its own getrusage.2. For older details of change
.\" history, etc, see getrlimit.2
.\"
.\" Modified 2004-11-16, mtk, Noted that the non-conformance
.\" when SIGCHLD is being ignored is fixed in 2.6.9.
.\"
.TH GETRUSAGE 2 2004-11-16 "Linux 2.6.9" "Linux Programmer's Manual"
.SH NAME
getrusage \- get resource usage
.SH SYNOPSIS
.B #include <sys/time.h>
.br
.B #include <sys/resource.h>
.sp
.BI "int getrusage(int " who ", struct rusage *" usage );
.SH DESCRIPTION
.PP
.BR getrusage ()
returns current resource usages, for a \fIwho\fP
of either
.B RUSAGE_SELF
or
.BR RUSAGE_CHILDREN .
The former asks for resources used by the current process,
the latter for resources used by those of its children
that have terminated and have been waited for.
.PP
.in +0.5i
.nf
struct rusage {
struct timeval ru_utime; /* user time used */
struct timeval ru_stime; /* system time used */
long ru_maxrss; /* maximum resident set size */
long ru_ixrss; /* integral shared memory size */
long ru_idrss; /* integral unshared data size */
long ru_isrss; /* integral unshared stack size */
long ru_minflt; /* page reclaims */
long ru_majflt; /* page faults */
long ru_nswap; /* swaps */
long ru_inblock; /* block input operations */
long ru_oublock; /* block output operations */
long ru_msgsnd; /* messages sent */
long ru_msgrcv; /* messages received */
long ru_nsignals; /* signals received */
long ru_nvcsw; /* voluntary context switches */
long ru_nivcsw; /* involuntary context switches */
};
.fi
.in -0.5i
.SH "RETURN VALUE"
On success, zero is returned. On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EFAULT
.I usage
points outside the accessible address space.
.TP
.B EINVAL
.I who
is invalid.
.SH "CONFORMING TO"
SVr4, 4.3BSD.
POSIX.1-2001 specifies
.BR getrusage (),
but only specifies the fields
.I ru_utime
and
.IR ru_stime .
.SH NOTES
Including
.I <sys/time.h>
is not required these days, but increases portability.
(Indeed,
.I struct timeval
is defined in
.IR <sys/time.h> .)
.PP
In Linux kernel versions before 2.6.9, if the disposition of
.B SIGCHLD
is set to
.B SIG_IGN
then the resource usages of child processes
are automatically included in the value returned by
.BR RUSAGE_CHILDREN ,
although POSIX.1-2001 explicitly prohibits this.
This non-conformance is rectified in Linux 2.6.9 and later.
.\" See the description of getrusage() in XSH.
.\" A similar statement was also in SUSv2.
.LP
The above struct was taken from 4.3BSD Reno.
Not all fields are meaningful under Linux.
In linux 2.4 only the fields
.IR ru_utime ,
.IR ru_stime ,
.IR ru_minflt ,
and
.IR ru_majflt
are maintained.
Since Linux 2.6,
.I ru_nvcsw
and
.I ru_nivcsw
are also maintained.
.SH "SEE ALSO"
.BR getrlimit (2),
.BR times (2),
.BR wait (2),
.BR wait4 (2)
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