Re: [boost] Lightweight futures

Subject: Re: [boost] Lightweight futures
From: Gavin Lambert (gavinl_at_[hidden])
Date: 2015-07-01 19:39:58

On 1/07/2015 22:29, Niall Douglas wrote:
> What you are missing is that we assume that whoever is calling
> get_future() must issue some form of memory synchronisation to
> transmit the newly constructed future to another thread. That
> synchronises the changed _needs_locks to other threads. I suppose it
> is possible that someone could send the future to one thread, and
> have a different thread do a state read and in theory the state
> reading thread doesn't see any new state.

The most common case is to transport the promise to another thread 
(sometimes via packaged_task) and to return the future on the calling 
thread.

I suppose designs that pass the future to another thread instead are 
possible but they seem a lot weirder and more convoluted.