vtimes (3) - Linux Manuals
vtimes: get resource usage
NAME
getrusage - get resource usage
SYNOPSIS
#include <sys/time.h>#include <sys/resource.h>
int getrusage(int who, struct rusage *usage);
DESCRIPTION
getrusage() returns resource usage measures for who, which can be one of the following:- RUSAGE_SELF
- Return resource usage statistics for the calling process, which is the sum of resources used by all threads in the process.
- RUSAGE_CHILDREN
- Return resource usage statistics for all children of the calling process that have terminated and been waited for. These statistics will include the resources used by grandchildren, and further removed descendants, if all of the intervening descendants waited on their terminated children.
- RUSAGE_THREAD (since Linux 2.6.26)
- Return resource usage statistics for the calling thread. The _GNU_SOURCE feature test macro must be defined (before including any header file) in order to obtain the definition of this constant from <sys/resource.h>.
The resource usages are returned in the structure pointed to by usage, which has the following form:
struct rusage {
Not all fields are completed;
unmaintained fields are set to zero by the kernel.
(The unmaintained fields are provided for compatibility with other systems,
and because they may one day be supported on Linux.)
The fields are interpreted as follows:
RUSAGE_THREAD
is Linux-specific.
Including
<sys/time.h>
is not required these days, but increases portability.
(Indeed,
struct timeval
is defined in
<sys/time.h>.)
In Linux kernel versions before 2.6.9, if the disposition of
SIGCHLD
is set to
SIG_IGN
then the resource usages of child processes
are automatically included in the value returned by
RUSAGE_CHILDREN,
although POSIX.1-2001 explicitly prohibits this.
This nonconformance is rectified in Linux 2.6.9 and later.
The structure definition shown at the start of this page
was taken from 4.3BSD Reno.
Ancient systems provided a
vtimes()
function with a similar purpose to
getrusage().
For backward compatibility, glibc (up until version 2.32) also provides
vtimes().
All new applications should be written using
getrusage().
See also the description of
/proc/[pid]/stat
in
proc(5).
RETURN VALUE
On success, zero is returned.
On error, -1 is returned, and
errno
is set appropriately.
ERRORS
ATTRIBUTES
For an explanation of the terms used in this section, see
attributes(7).
Interface Attribute Value
getrusage()
Thread safety MT-Safe CONFORMING TO
POSIX.1-2001, POSIX.1-2008, SVr4, 4.3BSD.
POSIX.1 specifies
getrusage(),
but specifies only the fields
ru_utime
and
ru_stime.
NOTES
Resource usage metrics are preserved across an
execve(2).
COLOPHON
This page is part of release 5.10 of the Linux
man-pages
project.
A description of the project,
information about reporting bugs,
and the latest version of this page,
can be found at
https://www.kernel.org/doc/man-pages/.