---
name: "sysinfo"
section: "2"
platform: "linux"
package: "man-pages"
version: "6.19-1"
release: "Arch Linux 2026-11-01"
platforms: ["linux"]
url: "https://new.carta.tech/sysinfo"
---

# sysinfo(2)

return system information

## 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

- **EFAULT**

  *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)](/proc/5.md)