fork()系统调用使用事例

最新推荐文章于 2025-09-06 21:44:10 发布

原创最新推荐文章于 2025-09-06 21:44:10 发布 · 311 阅读

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本文通过一个简单的C语言程序示例，演示了父进程与子进程间的变量共享情况。特别关注了fork系统调用后的变量行为，展示了在父子进程中变量是如何被复制的，并解释了为何在子进程中修改的变量不会影响到父进程中的变量值。

1 #include <stdio.h>
2 #include <sys/types.h>
3 #include <unistd.h>
4
5 int main()
6 {
7     int value=0;
8     int childpid;
9
10     fprintf(stderr,"the process before creating pid=%d/n",getpid());
11     if((childpid=fork())==0)
12     {
13         fprintf(stderr,"the child process pid=%d",getpid());
14         fprintf(stderr,"the initial value=%d/n",value);
15         value=1;
16
17         fprintf(stderr,"the value is %d after being changed by the child process/n",value);
18     }
19     else if(childpid>0)
20     {
21         fprintf(stderr,"the parent process pid=%d/n",getpid());
22         fprintf(stderr,"value in parent process is %d/n",value);
23     }else
24         fprintf(stderr,"the fork system call fail");
25     return 0;
26 }

//典型的运行结果

/*the process before creating pid=7151
the parent process pid=7151
value in parent process is 0
the child process pid=7152the initial value=0
the value is 1 after being changed by the child process*/