由进程名字获取进程 ID

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方法一：

pid_t getProcessPidbyName(char *name)
{
    FILE *fptr;
    char *buf = new char[255];
    char cmd[255] = {'\0'};
    pid_t pid = -1;
    sprintf(cmd,"pidof %s",name);
    if((fptr = popen(cmd,"r")) != NULL)
    {
        if(fgets(buf,255,fptr) != NULL)
        {
            pid = atoi(buf);
            printf("pid = %d\n",pid);
        }
    }

    pclose(fptr);
    delete buf;
    return pid;
}
/**********************************************************
* 来自：http://blog.csdn.net/bulreed/article/details/6682811
*
***********************************************************/

方法二：

int main()
{
    FILE *fp_handle;
    DIR *process_dir;
    struct dirent *ptr;

    SVPBool process_flag = SVP_FALSE;
    SVPChar buf[256] = {'\0'};
    SVPChar filepath[128] = {'\0'};
    SVPChar cur_task_name[128] = {'\0'};

    process_dir = opendir("/proc");
    if (SVP_NULL != process_dir)
    {
        while((ptr = readdir(process_dir)) != SVP_NULL) //循环读取路径下的每一个文件/文件夹
        {
            //如果读取到的是"."或者".."则跳过，读取到的不是文件夹名字也跳过
            if(DT_DIR != ptr->d_type)
                continue;
            if ((strcmp(ptr->d_name, ".") == 0) || (strcmp(ptr->d_name, "..") == 0))             
                continue;
            if(atoi(ptr->d_name) < 1130)
                continue;
            sprintf(filepath, "/proc/%s/status", ptr->d_name);//生成要读取的文件的路径
            fp_handle = fopen(filepath, "r");//打开文件
            if (NULL != fp_handle)
            {
                if( fgets(buf, 255, fp_handle)== SVP_NULL ){ //如果文件夹为空就跳过
                    fclose(fp_handle);
                    continue;
                }
                sscanf(buf, "%*s %s", cur_task_name);

                //如果文件内容满足要求则打印路径的名字（即进程的PID）
                if (strcmp(SVP_RCHMI_PROCESS_NAME, cur_task_name) == 0)
                {
                    process_flag = SVP_TRUE;
                    printf("PID:  %s\n", ptr->d_name);
                    fclose(fp_handle);
                    break;
                }
            }
        } 
    }
    closedir(process_dir);//关闭路径
    return process_flag;
}