sysinfo — returns information on overall system statistics
#include <sys/sysinfo.h>
int
sysinfo( |
struct sysinfo * | info); |
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_unitbytes.
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).
On success, zero is returned. On error, −1 is
returned, and errno is set
appropriately.
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.
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