sysinfo (2)

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.

SEE ALSO

proc(5)

Information

Source
Linux kernel
OS/version
Linux
Source updated
September 15, 2017
Page created
February 9, 2018
Page generated
December 2, 2018