Is pthread_cond_signal(3) man page correct?
Yuri
yuri at rawbw.com
Mon Feb 28 15:08:38 UTC 2011
On 28.02.11 2:41, Pieter de Goeje wrote:
> pthread_cond_signal() can indeed wake up more than one thread. That's why you
> should always wrap pthread_cond_wait() in a loop. For example a blocking
> queue could be implemented like this (pseudo code):
Thank you. Now its clear that POSIX allows multiple wake ups.
But my question is: why would the standard define it this way? Why would
it allow essentially arbitrary number of waiting threads to be woken up
by one event? I can't think of any practical app that would need "some
threads to be woken up". It would be natural to expect it to wake
exactly one thread. So the users won't need to have any special cycles
like you suggested in your previous post.
What is the underlying reason for POSIX to define it this way and for
OSes to implement it this way?
Yuri
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