Linux实验九(2)---使用fork，exit，exec系统调用编写多进程程序

步骤1：同上一节

步骤2：建立目录

　　cd workdir/linux/application

　　mkdir -p 9-process/fork

步骤3：复制

　　cp  /mnt/hgfs/share/2.Linux实验部分/09.Linux系统fork等系统实验调用实验/实验代码/93.c 9-process/fork -a

步骤4：执行

　　gcc 93.c -o fork

　　./fork

附：程序源码

　　93.c

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

int    global=22;
char    buf[]="the test content!\n";

int main(void)
{    
    int test=0,stat;
    pid_t pid;
    if(write(STDOUT_FILENO, buf, sizeof(buf)) != sizeof(buf))
    {  perror("write error!"); }
    printf(" fork test!\n");
    /* fork */
    pid = fork();   /*we should check the error*/
    if (pid == -1)
    {
        perror("fork");
        exit(0);    
    }
    else if (pid == 0)
    {
        global++;   test++;
        printf("global=%d test=%d Child,my PID is %d\n",global,test,getpid());
        exit(0);
    }
    /*else be the parent*/
    global+=2;
    test+=2;
    printf("global=%d test=%d Parent,my PID is %d\n",global,test,getpid());
    exit(0);
    //printf("global=%d test=%d Parent,my PID is %d",global,test,getpid());
    //_exit(0);
}