关于pthread_cleanup_push注册的清理函数被执行的疑问

tklist

网上查资料说：
pthread_cleanup_push来注册清理函数。在以下三种情形之一发生时，注册的清理函数被执行：
    1）调用pthread_exit。
    2）作为对取消线程请求(pthread_cancel)的响应。
    3）以非0参数调用pthread_cleanup_pop。
在线程宿主函数中主动调用return，如果return语句包含在pthread_cleanup_push()/pthread_cleanup_pop()对中，则不会引起清理函数的执行，反而会导致segment fault。
<--------------------------------------------------------->
但是我自己试了如果是return操作也是会调用注册清理函数，没有报什么错。有人试过吗？

linux_c_py_php

       A cancellation clean-up handler is popped from the stack and executed in the following circumstances:

       1. When a thread is canceled, all of the stacked clean-up handlers are popped and executed in the reverse of  the
          order in which they were pushed onto the stack.

       2. When  a  thread  terminates by calling pthread_exit(3), all clean-up handlers are executed as described in the
          preceding point.  (Clean-up handlers are not called if the thread terminates by performing a return  from  the
          thread start function.)

       3. When  a  thread  calls pthread_cleanup_pop() with a nonzero execute argument, the top-most clean-up handler is
          popped and executed.     


  POSIX.1 says that the effect of using return, break, continue, or goto to prematurely  leave  a  block  bracketed
       pthread_cleanup_push() and pthread_cleanup_pop() is undefined.  Portable applications should avoid doing this.

tklist

回复 2# linux_c_py_php
看了您的解答，我没能理解这个(Clean-up handlers are not called if the thread terminates by performing a return  from  the thread start function.)
看最后的文字是说尽量避免使用 return, break, continue,  goto等操作离开定义的块。

   

linux_c_py_php

POSIX.1 says that the effect of using return, break, continue, or goto to prematurely  leave  a  block  bracketed
       pthread_cleanup_push() and pthread_cleanup_pop() is undefined.  Portable applications should avoid doing this.