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getrusage (2)
GETRUSAGE(2) Linux Programmer's Manual GETRUSAGE(2)
NAME
getrusage - get resource usage
SYNOPSIS
#include <sys/time.h>
#include <sys/resource.h>
int getrusage(int who, struct rusage *usage);
DESCRIPTION
getrusage() returns current resource usages, for a who of either
RUSAGE_SELF or 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.
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 */
};
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is
set appropriately.
ERRORS
EFAULT usage points outside the accessible address space.
EINVAL who is invalid.
CONFORMING TO
SVr4, 4.3BSD. POSIX.1-2001 specifies getrusage(), but only specifies
the fields ru_utime and ru_stime.
NOTES
Including <sys/time.h> is not required these days, but increases porta-
bility. (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 automat-
ically included in the value returned by RUSAGE_CHILDREN, although
POSIX.1-2001 explicitly prohibits this. This non-conformance is recti-
fied in Linux 2.6.9 and later.
The above struct was taken from 4.3BSD Reno. Not all fields are mean-
ingful under Linux. In linux 2.4 only the fields ru_utime, ru_stime,
ru_minflt, and ru_majflt are maintained. Since Linux 2.6, ru_nvcsw and
ru_nivcsw are also maintained.
SEE ALSO
getrlimit(2), times(2), wait(2), wait4(2)
Linux 2004-11-16 GETRUSAGE(2)
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