NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | ERRORS | VERSIONS | CONFORMING TO | NOTES | SEE ALSO | COLOPHON

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

NAME         top

       sysinfo - return system information

SYNOPSIS         top

       #include <sys/sysinfo.h>

       int sysinfo(struct sysinfo *info);

DESCRIPTION         top

       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         top

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

ERRORS         top

       EFAULT info is not a valid address.

VERSIONS         top

       sysinfo() first appeared in Linux 0.98.pl6.

CONFORMING TO         top

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

NOTES         top

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

SEE ALSO         top

       proc(5)

COLOPHON         top

       This page is part of release 4.10 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/.

Linux                            2016-07-17                       SYSINFO(2)