调用 system() 后程序不执行任何操作 [英] program not executing anything after a call to system()

问题描述

我正在通过系统(命令)调用调用命令.但是在这个 system() 调用之后没有其他代码被执行.

为什么会这样?我认为，system() 会为命令"执行创建一个子进程，而我的程序(命令"-子进程的父进程)将在此之后继续执行代码.

我没有正确理解 system() 吗?

代码:

printf("before 
");system("tail -f 文件名");/* 长寿 - 永不返回 */printf("在
之后");

在这里，我在打印后没有看到.

解决方案

system(3) 函数使您的进程等待子进程的完成.

编辑 0:

你必须使用经典的一对 fork(2) 和 execve(2) 用于您想要做什么.您还可以检查您的 C 库是否提供 POSIX spawn(3).>

编辑 1:

查看waitpid(2) 让父母在身边.

I am calling a command via system(command) call. But no other code is executed after this system() call.

Why is so? I thought, system() would create a child process for "command" execution and my program (parent of "command"-child) will continue executing code after that.

Am I not understanding system() correctly?

code:

printf("before 
");
system("tail -f filename");       /* long lived - never returns */
printf("after 
");

Here, I do not see after getting printed ever.

解决方案

The system(3) function causes your process to wait for the completion of the child.

Edit 0:

You have to use the classic pair of fork(2) and execve(2) for what you want to do. You might also check whether your C library provides POSIX spawn(3).

Edit 1:

Look into waitpid(2) to keep the parent around.

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