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SYSINFO (2) | System calls | Unix Manual Pages | :man

NAME

sysinfo - returns information on overall system statistics

CONTENTS

Synopsis
Description
Errors

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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