sysinfo

SYSINFO(2)                 Linux Programmer's Manual                SYSINFO(2)



NAME
       sysinfo - returns information on overall system statistics

SYNOPSIS
       #include <sys/sysinfo.h>

       int sysinfo(struct sysinfo *info);

DESCRIPTION
       Until Linux 2.3.16, sysinfo used to return 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 */
              };

       and the sizes were given in bytes. Since Linux  2.3.23  (i386),  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 for libc5 */
              };

       and the sizes are given as multiples of mem_unit bytes.

       sysinfo  provides  a  simple  way of getting overall system statistics.
       This is more portable than reading /dev/kmem.  For an  example  of  its
       use, see intro(2).

RETURN VALUE
       On  success,  zero is returned.  On error, -1 is returned, and errno is
       set appropriately.

ERRORS
       EFAULT pointer to struct sysinfo is invalid

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

       The  Linux kernel has a sysinfo system call since 0.98.pl6.  Linux libc
       contains a sysinfo() routine since 5.3.5, and glibc has one since 1.90.

SEE ALSO
       proc(5)



Linux 2.0                         1997-08-25                        SYSINFO(2)