Re: [boost] [thread] semaphore

Subject: Re: [boost] [thread] semaphore
From: Michael Marcin (mike.marcin_at_[hidden])
Date: 2013-09-17 21:23:25

On 7/8/2013 4:04 AM, Tim Blechmann wrote:
> hi all,
>
> i've submitted an implementation of semaphores for boost.thread to trac
> [1]. they provide an interface similar to boost.interprocess semaphores,
> with the exception of having chrono-style try_wait_for and
> try_wait_until members for timed_wait.
>
> the patch provides the following implementations:
> * win32 semaphores (tested with windows 8)
> * posix semaphores (tested with linux)
> * dispatch semaphores (tested with osx 10.8)
> * mutex/condition_variable/counter emulation
>
> the native implementations are much faster than the fallback, in
> microbenchmarks with high contention, i've seen a speedup of 30 to 80.
>
> would be great if they can be incorporated into boost.thread.
> comments/suggestions on the API are highly appreciated.
>

As I understood the reason semaphores were not included in c++11 was 
because they were too hard to use and the recommendation is to just use 
condition_variable instead.

What is wrong with guidance that would lead us back to wanting to use 
semaphores?