处理异步信号在多线程程序

问题描述

Linux的编程接口本书中提到的方法与异步信号在多线程程序进行处理：

Now the questions:

1. when kernel wants to deliver signals it choose one of the threads inside process arbitrary. from where it can know to deliver signal to the dedicated thread?
2. pthread API is non-aync-safe functions. so how we can use them inside signal handler?

解决方案

When the kernel delivers a process-directed signal, it chooses one of the threads that does not have the signal blocked. This means that it never chooses any of the threads apart from the signal-handling thread (which acts like it has the signal unblocked while it is blocked in sigwaitinfo() or similar). In other words: the kernel knows where to deliver the signal, because you have arranged things such that the signal-handling thread is the only thread that is ever allowed to deliver the signal to.

You do not use the pthreads API, or any non-async-signal-safe functions in a signal handler. The solution outlined does not handle the signals within signal handlers - it handles the signals within the normal execution flow of the signal-handling thread, after sigwaitinfo() returns. This allows it to access non-async-signal-safe functions, which is the whole point.

这篇关于处理异步信号在多线程程序的文章就介绍到这了，希望我们推荐的答案对大家有所帮助，也希望大家多多支持！