1. Function introduction
Obtain system memory usage through the sysinfo function.
The help page of the sysinfo function is as follows:
wbyq@wbyq:/mnt/hgfs/linux-share-dir/linux_c$ man sysinfo
SYSINFO(2) Linux Programmer's Manual SYSINFO(2)
NAME
sysinfo - return system information
SYNOPSIS
#include <sys/sysinfo.h>
int sysinfo(struct sysinfo *info);
DESCRIPTION
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.Second, the program source code
#include <stdio.h>
#include <stdlib.h>
#include <unistd.h>
#include <sys/sysinfo.h>
int main(int argc,char **argv)
{
/*2. 获取当前系统内存使用情况*/
struct sysinfo s_info;
char info_buff[100];
while(1)
{
if(sysinfo(&s_info)==0)
{
sprintf(info_buff,"总内存: %.ld M",s_info.totalram/1024/1024);
printf("%s\n",info_buff);
sprintf(info_buff,"未使用内存: %.ld M",s_info.freeram/1024/1024);
printf("%s\n",info_buff);
sprintf(info_buff,"交换区总内存: %.ld M",s_info.totalswap/1024/1024);
printf("%s\n",info_buff);
sprintf(info_buff,"交换区未使用内存: %.ld M",s_info.freeswap/1024/1024);
printf("%s\n",info_buff);
sprintf(info_buff,"系统运行时间: %.ld 分钟",s_info.uptime/60);
printf("%s\n",info_buff);
printf("\n\n");
}
sleep(1);
}
return 0;
}
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