SYSINFO

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
ERRORS
CONFORMING TO
SEE ALSO

NAME

sysinfo − returns information on overall system statistics

SYNOPSIS

#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 for libc5 */

};

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. For an example of its use, see intro(2).

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

CONFORMING TO

This function is Linux-specific, and should not be used in programs intended to be portable.

The Linux kernel has a sysinfo system call since 0.98.pl6. Linux libc contains a sysinfo() routine since 5.3.5, and glibc has one since 1.90.

SEE ALSO

proc(5)






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