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SYSINFO

Section: Linux Programmer's Manual (2)
Updated: 2017-09-15
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NAME

sysinfo - return system information

SYNOPSIS

#include <sys/sysinfo.h>

int sysinfo(struct sysinfo *info);

DESCRIPTION

sysinfo() returns certain statistics on memory and swap usage, as well as the load average.

Until Linux 2.3.16, sysinfo() returned 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 */ };

In the above structure, the sizes of the memory and swap fields are given in bytes.

Since Linux 2.3.23 (i386) and Linux 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 */ };

In the above structure, sizes of the memory and swap fields are given as multiples of mem_unit bytes.

RETURN VALUE

On success, sysinfo() returns zero. On error, -1 is returned, and errno is set to indicate the cause of the error.

ERRORS

EFAULT: info is not a valid address.

VERSIONS

sysinfo() first appeared in Linux 0.98.pl6.

CONFORMING TO

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

NOTES

All of the information provided by this system call is also available via /proc/meminfo and /proc/loadavg.

COLOPHON

This page is part of release 4.13 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/.