popen函数:确保同一个进程只启动一次

#include <string.h>
#include <stdio.h>
#include <stdlib.h>

int main(int argc, char ** agrgv)
{
    int        iRet = -1;
    if(argc < 3)
    {
        printf("参数个数不对! 应为3个!\n");
        return -1;
    }
    printf("argv[0]=[%s]\n", agrgv[0]);
    printf("argv[1]=[%s]\n", agrgv[1]);
    printf("argv[2]=[%s]\n", agrgv[2]);

    iRet = check_process();
    printf("iRet = [%d]\n", iRet);
    if ( iRet != 0 )
    {
        return -1;
    }
    while(1);
    return 0;
}

int check_process()
{
    int        i;
    FILE *    fp = NULL;
    fp = popen( "ps -ef|grep test|grep QHYS|grep 10004|grep -v grep|wc" ,"r");
    fscanf(fp,"%d",&i);
    printf("***********i=[%d]*******************\n",i);
    if (i>1)
    {
        printf("主机前置进程存在!不容许再启动\n");
        pclose(fp);
        return -1;
    }
    pclose(fp);
    return 0;
}