GNU/Linux |
CentOS 5.2 |
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sysinfo(2) |
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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_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).
On success, zero is returned. On error, −1 is returned, and errno is set appropriately.
EFAULT |
pointer to struct sysinfo is invalid |
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.
proc(5)
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sysinfo(2) | ![]() |