Re: [boost] [thread] boost::future::then

Subject: Re: [boost] [thread] boost::future::then
From: Vicente J. Botet Escriba (vicente.botet_at_[hidden])
Date: 2015-10-09 16:01:50

Le 09/10/15 16:16, Mikael Olenfalk a écrit :
> On Fri, Oct 9, 2015 at 3:44 PM, Vladimir Prus <vladimir.prus_at_[hidden]>
> wrote:
>
>> On 09-Oct-15 4:02 PM, Mikael Olenfalk wrote:
>> ...
>>
>>> I might have misunderstood the question but I would assume a solution
>>> would
>>> be to build boost.thread with executors enabled[1]. And then wrap the QT
>>> event loop in an executor interface[2] and use the
>>> boost::future<T>::then(Executor&, ...) overload.
>>>
>> Mikael,
>>
>> thanks for the response. I suppose it would work - although if I need to
>> pass this
>> executor any time I call 'then', it become rather awkward rather quickly.
>> It would
>> be nicer if promise could have an executor, and pass it to future and then
>> to futures returned by 'then', so that I only need to to specify custom
>> behaviour
>> when creating a promise - that can be easily wrapped in a function.
>>
>>
> I don't think so, I had a very quick look but didn't see anything.
See my replay to Vladimir.
>
>
>> Do you have any comments on presence or absence of bugs, and overall API
>> maturity?
>> Having to define macros to get useful functionality is not quite perfect.
>>
> I have barely played with it, I got little bit discouraged on using it at
> work as it required enabled undocumented feature macros.
Please, next time you find things like that please post on this ML or 
create a ticket.
Anyway, I'm sure that there are a lot of error in the documentation. 
What is not documented for you?
> Also it seemed to
> me that it actually didn't compile in VS2015 (which is what I use).
You know I started this some time ago and deliver the  first version for 
boost 1.53 (if Vladimir is right).
Since then, there have been a lot of compiler versions that have been 
released.  We do as much as possible to write portable code, but no MSVC 
version is satisfactory, there is always some feature missing or not 
working completely.

I'm afraid but since more than 3 years I don't have a Windows machine to 
develop, so I can just try and see what the regression said me.
You can see the results on 
http://www.boost.org/development/tests/develop/developer/thread.html.
The results are no so bad for MSVC. There are some lambda issues.

> My
> guess is that it is very much still experimental code.
All the executor stuff is really experimental and I have plans to change 
a little bit the interface to adhere to the Concurrency TS (once they 
decide the interface).
>
> If you play with it some more I am very interested in your findings.
Me too ;-)
> If you
> also happen to figure out how to combine it with boost::asio::io_service I
> would be very interested in hearing your findings, we have a (global)
> worker-pool-thingie at work which uses io_service and I would like to make
> boost::async(Executor& ex, C...) work with it so that usage becomes
> nicer/simpler.
>
> I guess the author of Boost.Thread is hanging out on this mailing list,
> maybe (s)he can comment on status?
>
>
Here I am.

Vicente