linux sysinfo函数使用方法－－获取内存大小

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Linux中,sysinfo是用来获取系统相关信息的结构体。

函数声明和原型：

#include <sys/sysinfo.h>

int sysinfo(struct sysinfo *info);

结构体信息：

在Linux 2.3.16中，结构体的信息是（单位是字节）：

struct sysinfo {

long uptime;

/* 启动到现在经过的时间 */

unsigned long loads[3];
/* 1, 5, and 15 minute load averages */

unsigned long totalram; /* 总的可用的内存大小 */

unsigned long freeram; /* 还未被使用的内存大小 */

unsigned long sharedram; /* 共享的存储器的大小 */

unsigned long bufferram; /* 缓冲区大小 */

unsigned long totalswap; /* 交换区大小 */

unsigned long freeswap; /* 还可用的交换区大小 */

unsigned short procs; /* 当前进程数目 */

char _f[22]; /* 64字节的补丁结构 */

};

在Linux 2.3.23(i386), 2.3.48 (all architectures)中，结构体的信息是（单位是mem_unit字节）：

struct sysinfo {

long uptime; /* 启动到现在经过的时间 */

unsigned long loads[3];
/* 1, 5, and 15 minute load averages */

unsigned long totalram; /* 总的可用的内存大小 */

unsigned long freeram; /* 还未被使用的内存大小 */

unsigned long sharedram; /* 共享的存储器的大小*/

unsigned long bufferram; /* 共享的存储器的大小 */

unsigned long totalswap; /* 交换区大小 */

unsigned long freeswap; /* 还可用的交换区大小 */

unsigned short procs; /* 当前进程数目 */

unsigned long totalhigh; /* 总的高内存大小 */

unsigned long freehigh; /* 可用的高内存大小 */

unsigned int mem_unit; /* 以字节为单位的内存大小 */

char _f[20-2*sizeof(long)-sizeof(int)];
/* libc5的补丁

};

返回值：

操作成功返回0，错误返回-1；

样例：

#include <stdio.h>

#include <linux/unistd.h> /* 包含调用 _syscallX 宏等相关信息*/

#include <linux/kernel.h> /* 包含sysinfo结构体信息*/

_syscall1(int, sysinfo, struct sysinfo*, info);

//using namespace std;

int main(int argc, char *agrv[])

{

struct sysinfo s_info;

int error;

error = sysinfo(&s_info);

printf("\n\ncode error=%d\n",error);

printf("Uptime = %ds\nLoad: 1 min%d / 5 min %d / 15 min %d\n"

"RAM: total %d / free %d /shared%d\n"

"Memory in buffers = %d\nSwap:total%d/free%d\n"

"Number of processes = %d\n",

s_info.uptime, s_info.loads[0],

s_info.loads[1], s_info.loads[2],

s_info.totalram, s_info.freeram,

s_info.totalswap, s_info.freeswap,

s_info.procs );

return 0;

}

/*输出结果：

/home/chenhd/future> ./Sysinfo_1

code error=0

Uptime = 154s

Load: 1 min22976 / 5 min 13888 / 15 min 5408

RAM: total 128307200 / free 55656448 /shared263168000

Memory in buffers = 263168000

Swap:total50/free1073821804

Number of processes = 1073823352

/home/chenhd/future>

*/

// an example

int main()

{

FILE *fp;

char str[81];

memset(str,0,81);

fp=popen("cat /proc/meminfo | grep MemTotal:|sed -e 's/.*:[^0-9]//'","r");

if(fp < 0)

{

printf("无法读取ram信息\n");

exit(1);

}

fgets(str,80,fp);

fclose(fp);

if (cpuinfo != NULL)

{

strncpy(cpuinfo,str,80);

}

#include <linux/unistd.h> /* 包含调用 _syscallX 宏等相关信息*/

#include <linux/kernel.h> /* 包含sysinfo结构体信息*/

#include <sys/sysinfo.h>

struct sysinfo s_info;

int error;

error = sysinfo(&s_info);

gulong spd=atoi(str);

printf("您ram是%lu kb %s %lu\n",spd, str, s_info.totalram);

return spd;

}