Mywaitpid(linux).txt

#include<stdio.h>
#include<unistd.h>
#include<stdlib.h>
#include<sys/types.h>
#include<sys/wait.h>

int main()
{
        pid_t id=fork();
        if(id==0)
        {//child
          while(1)
          {
          printf("this is child id:%d\n",getpid());
          sleep(4);
          }
        }
        else
        {//father
        printf("i am father i am waitting...\n ");
                int status = 0;    //[*]
        //      do
        //      {
                //pid_t ret = wait(&status);
                pid_t ret=wait(&status); //[*] pay attention to this "id"
            //  if(ret==0)
                  //  { 
                        //   printf("fatherproc is running...\n");
                          // sleep(1);
                        //}
                    if(ret>0)
                    {
                        printf("waitting success!\n");
                        sleep(1);
                         if(WIFEXITED(status))
                        {
                            printf("child is exited!  exitcode:%d\n",WEXITSTATUS(status));
                            return 0;
                        }
                    }
                    else
                    {
                           perror("waitfalse!");
                           return 0;
                    }
            //  }while(1);
        }
        return 0;
}