让父母等待所有子进程 [英] Make parent wait for all child processes

问题描述

我希望有人能阐明如何使家长等待所有的子进程后叉继续之前完成一些轻。我有清理code，我想运行，但子进程需要有返回之前会发生这种情况。

 的for（int n = 0; ID和LT; N; ID ++）{
  如果（叉（）== 0）{
    //子
    出口（0）;
  }其他{
    //父
    ...
  }
  ...
}
 

解决方案

POSIX定义一个函数：等待（NULL）; 。它是 waitpid函数（-1，NULL，0）的简写; ，这将阻塞，直到所有的孩子处理退出

。

在你的情况，有家长从内部调用它的其他分支。

I'm hoping someone could shed some light on how to make the parent wait for ALL child processes to finish before continuing after the fork. I have cleanup code which I want to run but the child processes need to have returned before this can happen.

for (int id=0; id<n; id++) {
  if (fork()==0) {
    // Child
    exit(0);      
  } else {
    // Parent
    ...
  }
  ...
}

解决方案

POSIX defines a function: wait(NULL)；. It's shorthand for waitpid(-1, NULL, 0);, which will block until all children processes exit.

In your case, have the parent call it from within your else branch.

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