.\" -*- nroff -*-
.\"
.\" (C)opyright 1993 by Dan Miner (dminer@nyx.cs.du.edu)
.\"
.\"  Permission is granted to freely distribute or modify this file
.\"  for the purpose of improving Linux or its documentation efforts.
.\"  If you modify this file, please put a date stamp and HOW you
.\"  changed this file.  Thanks.   -DM
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.\" Modified Sat Jul 24 12:35:12 1993 by Rik Faith <faith@cs.unc.edu>
.\" Modified Tue Oct 22 22:29:51 1996 by Eric S. Raymond <esr@thyrsus.com>
.\" Modified Mon Aug 25 16:06:11 1997 by Nicolás Lichtmaier <nick@debian.org>
.\"
.TH SYSINFO 2 2007-11-15 "Linux" "Linux Programmer's Manual"
.SH NAME
sysinfo \- returns information on overall system statistics
.SH SYNOPSIS
.B #include <sys/sysinfo.h>
.sp
.BI "int sysinfo(struct sysinfo *" info );
.SH DESCRIPTION
Until Linux 2.3.16,
.BR sysinfo ()
used to return information in the following structure:

.nf
.in +4n
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
.fi
.PP
and the sizes were given in bytes.

Since Linux 2.3.23 (i386), 2.3.48
(all architectures) the structure is:

.nf
.in +4n
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 */
};
.in
.fi
.PP
and the sizes are given as multiples of \fImem_unit\fP bytes.

.BR sysinfo ()
provides a simple way of getting overall system statistics.
This is more
portable than reading \fI/dev/kmem\fP.
.SH "RETURN VALUE"
On success, zero is returned.
On error, \-1 is returned, and
.I errno
is set appropriately.
.SH ERRORS
.TP
.B EFAULT
pointer to \fIstruct\ sysinfo\fP is invalid
.SH "CONFORMING TO"
This function is Linux-specific, and should not be used in programs
intended to be portable.
.sp
The Linux kernel has a
.BR sysinfo ()
system call since 0.98.pl6.
Linux libc contains a
.BR sysinfo ()
routine since 5.3.5, and
glibc has one since 1.90.
.SH "SEE ALSO"
.BR proc (5)