p6-9.c

UNIX程序设计教程

#include <sys/types.h>
#include <unistd.h>
#include <stdlib.h>
#include <stdio.h>
int main(void)
{
        pid_t pid;
        char  *message;
        int   n;
        printf("fork program starting\n");
        pid = fork();
        switch(pid){
        case -1:         
                exit(EXIT_FAILURE);
        case 0:        
                message = "This is child";
                n = 2;
                break;
        default:
                message = "This is parent";
                sleep();
                n = 5;
                break;
        }
        for (; n>0; n--) {
                puts(message);
                sleep(n-1);
        }
        exit(EXIT_SUCCESS);
}