系统编程之进程管理 wait（）

#include<unistd.h>

#include <sys/types.h>

#include <sys/wait.h>

#include <stdio.h>

#include <stdlib.h>

#include <math.h>

#include <errno.h>

int main()

{

    pid_t child;

    /*创建子进程*/

    if((child=fork())==-1)

    {

        printf("Fork Error:%s\n",strerror(errno));

        exit(1);

    }

    else

        if (child == 0) //child

        {

            printf("the child process is running \n");

            sleep(1);

            printf("I am the chil: %d\n",getpid());

            exit(0);

        }

        else //parament

        {

            wait(NULL);//等到任一子进程退出，父进程才会运行

          //  waitpid(child,NULL,0); //等待特定的进程

            printf("the father process starts run\n");

            printf("I am the father: %d\n",getpid());

            return 0;

        }

}