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sysinfo函數使用方法

1、Linux中,sysinfo是用來獲取系統相關信息的結構體。

函數聲明和原型:

int sysinfo(struct sysinfo *info);

返回值:操作成功返回0,錯誤返回-1;

2、結構體信息:

在Linux 2.3.16中,結構體的信息是(單位是字節):

struct sysinfo {

long uptime; /* 啟動到現在經過的時間 */

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

unsigned long totalram; /* 總的可用的內存大小 */

unsigned long freeram; /* 還未被使用的內存大小 */

unsigned long sharedram; /* 共享的存儲器的大小 */

unsigned long bufferram; /* 緩沖區大小 */

unsigned long totalswap; /* 交換區大小 */

unsigned long freeswap; /* 還可用的交換區大小 */

unsigned short procs; /* 當前進程數目 */

char _f[22]; /* 64字節的補丁結構 */

};

在Linux 2.3.23(i386), 2.3.48 (all architectures)中,結構體的信息是(單位是mem_unit字節):

struct sysinfo {

long uptime; /* 啟動到現在經過的時間 */

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

unsigned long totalram; /* 總的可用的內存大小 */

unsigned long freeram; /* 還未被使用的內存大小 */

unsigned long sharedram; /* 共享的存儲器的大小*/

unsigned long bufferram; /* 共享的存儲器的大小 */

unsigned long totalswap; /* 交換區大小 */

unsigned long freeswap; /* 還可用的交換區大小 */

unsigned short procs; /* 當前進程數目 */

unsigned long totalhigh; /* 總的高內存大小 */

unsigned long freehigh; /* 可用的高內存大小 */

unsigned int mem_unit; /* 以字節為單位的內存大小 */

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

};

樣例1:

#include

#include /* 包含調用 _syscallX 宏等相關信息*/

#include /* 包含sysinfo結構體信息*/

_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;

}

/*輸出結果:

/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>

*/

樣例2:計算系統啟動時間的方法

#include

#include

struct sysinfo s_info;

long uptime;

int d,h,m,s;

int main()

{

if(0==sysinfo(&s_info))

{

uptime=s_info.uptime;

d=uptime/(3600*24);

h=(uptime/3600)%24;

m=(uptime%3600)/60;

s=(uptime%3600)%60; //由此可見uptime不是秒

printf("d=%d:h=%d:m=%d:s=%d",d,h,m,s);

return 0;

}

return -1;

}

運行結果:

$ gcc -o uptime uptime.c

$ ./uptime

d=19:h=0:m=4:s=52

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