sysinfo (2)
Leading comments
Copyright (C) 2016, Michael Kerrisk <mtk.manpages@gmail.com> Based on an earlier version of the page where a few pieces were copyright (C) 1993 by Dan Miner (dminer@nyx.cs.du.edu) and subsequently others (see old changelog below). The structure definitions are taken more or less straight from the kernel source files. %%%LICENSE_START(VERBATIM) Permission is granted to make and distribute verbatim copies of this manual provided the copyright notice and this permission notice are preserved on ...
NAME
sysinfo - returns information on overall system statisticsSYNOPSIS
#include <sys/sysinfo.h>int sysinfo(struct sysinfo *info);
DESCRIPTION
Until Linux 2.3.16, sysinfo() used to return information in the following structure:
struct sysinfo {
long uptime; /* Seconds since boot */
unsigned long loads[3]; /* 1, 5, and 15 minute load averages */
unsigned long totalram; /* Total usable main memory size */
unsigned long freeram; /* Available memory size */
unsigned long sharedram; /* Amount of shared memory */
unsigned long bufferram; /* Memory used by buffers */
unsigned long totalswap; /* Total swap space size */
unsigned long freeswap; /* swap space still available */
unsigned short procs; /* Number of current processes */
char _f[22]; /* Pads structure to 64 bytes */
};
and the sizes were given in bytes.
Since Linux 2.3.23 (i386), 2.3.48
(all architectures) the structure is:
struct sysinfo {
long uptime; /* Seconds since boot */
unsigned long loads[3]; /* 1, 5, and 15 minute load averages */
unsigned long totalram; /* Total usable main memory size */
unsigned long freeram; /* Available memory size */
unsigned long sharedram; /* Amount of shared memory */
unsigned long bufferram; /* Memory used by buffers */
unsigned long totalswap; /* Total swap space size */
unsigned long freeswap; /* swap space still available */
unsigned short procs; /* Number of current processes */
unsigned long totalhigh; /* Total high memory size */
unsigned long freehigh; /* Available high memory size */
unsigned int mem_unit; /* Memory unit size in bytes */
char _f[20-2*sizeof(long)-sizeof(int)]; /* Padding to 64 bytes */
};
and the sizes are given as multiples of mem_unit bytes.
sysinfo()
provides a simple way of getting overall system statistics.
This is more
portable than reading /dev/kmem.
RETURN VALUE
On success, zero is returned. On error, -1 is returned, and errno is set appropriately.ERRORS
- EFAULT
- pointer to struct sysinfo is invalid