Re: Newbie needs pointer to currently executing thread.

From: dmoore99atwork (dmoore_at_[hidden])
Date: 2002-04-09 20:53:26

--- In Boost-Users_at_y..., dick.bridges_at_t... wrote:
> Threads in a thread_group - derived pool are waiting on a condition.
> Condition gets notify_one().  How do I get id/pointer for the 
thread that
> was released?  I've got a feeling I'm gonna be *REAL* embarrassed 
when I
> find out, but I can't figure it out.
> 
> Thanks for any help.

Dick,

In general, condition variables (both the Boost.Threads version and 
the POSIX version) don't tell the "notifier" which thread woke up.

That's not necessarily a problem, though.  A thread pool usually 
implies a set of threads that are equivalent in some way, even 
running the same thread function.

Referring to the example at:
http://www.boost.org/libs/thread/doc/condition.html#Example, 

Take a look the the receive() function.

while (buffered == 0)
   buffer_not_empty.wait(lk);

You might have three threads which reach this point when buffered==0 
(meaning the buffer is empty).   When a new sender in a fourth thread 
adds something to the buffer and calls notify_one(), exactly one of 
the three threads waiting on the condition will wake up and do some 
work.  You won't care which thread wakes up, because any one of them 
will be prepared to do the necessary work.

If this doesn't get you unstuck, please post more details, in 
particular why you feel it is important to know which thread "woke up"

Regards,
Dave