Re: [Boost-users] Re: Re: Semaphore and barriers for boost-threads?

From: Craig Rodrigues (rodrigc_at_[hidden])
Date: 2004-02-18 11:33:25

On Wed, Feb 18, 2004 at 06:15:58PM +0300, Vladimir Prus wrote:
> The interesting part of "POSIX on semaphores" is in 
> 
>     http://tinyurl.com/2s89
> 
> Look the the phrase "Much experience with semaphores shows" and futher
> paragraphs. In essense, it's says that semaphores are for signal handlers
> and for inter-process synchronization and discourages their use anywhere
> else.

That's an interesting link, thanks!
I don't interpret the text in the same way that you do, but
maybe I am not understanding something properly.

Further down from "Much experience with semaphores shows",
there is this text:

"Counting semaphores are well matched to dealing with producer/consumer
problems, including those that might exist between threads of
different processes, or between a signal handler and a thread. In
the former case, there may be little or no memory shared by the
processes; in the latter case, one is not communicating between
co-equal threads, but between a thread and an interrupt-like entity.
It is for these reasons that IEEE Std 1003.1-2001 allows semaphores
to be used by threads."

This is the use-case that I am interested in. 

-- 
Craig Rodrigues        
http://crodrigues.org
rodrigc_at_[hidden]