Manpages - sysinfo.2

sysinfo - return system information

  #include <sys/sysinfo.h>

  int sysinfo(struct sysinfo *info);

*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.

On success, *sysinfo*() returns zero. On error, -1 is returned, and errno is set to indicate the error.

EFAULT

info is not a valid address.

*sysinfo*() first appeared in Linux 0.98.pl6.

This function is Linux-specific, and should not be used in programs intended to be portable.

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

*proc*(5)

This page is part of release 5.13 of the Linux man-pages project. A description of the project, information about reporting bugs, and the latest version of this page, can be found at https://www.kernel.org/doc/man-pages/.