Manual Reference Pages  - SYSINFO (2)

NAME

sysinfo - returns information on overall system statistics

CONTENTS

Synopsis
Description
Errors
Colophon

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 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

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)

COLOPHON

This page is part of release 3.44 of the Linux man-pages project. A description of the project, and information about reporting bugs, can be found at http://www.kernel.org/doc/man-pages/.


Linux SYSINFO (2) 2012-05-05
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