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sysinfo(2) System Calls Manual sysinfo(2)

NAME

sysinfo - return system information

LIBRARY

Standard C library (libc, -lc)

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 error.

ERRORS

info is not a valid address.

STANDARDS

Linux.

HISTORY

Linux 0.98.pl6.

NOTES

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

SEE ALSO

proc(5)

2024-05-02 Linux man-pages 6.8