| SYSINFO(2) | Linux Programmer's Manual | 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 cause of the error.
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.
This page is part of release 4.16 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/.
| 2017-09-15 | Linux |