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

On 09-Oct-15 4:02 PM, Mikael Olenfalk wrote:

On Fri, Oct 9, 2015 at 9:43 AM, Vladimir Prus wrote:

...

In particular, suppose I have this:

// Thread 1

boost::promise<int> pi; boost::future<int> fi = pi.get_future();

// pass pi to thread 2 somehow

fi.then(....);

// Thread 2

pi.set_value(100);

And I want continuation to be executed in thread 1, assuming that thread 1 runs Qt event loop, allowing me to use QTimer::singleShot, or queued signal, or similar mechanism. How would I go about making boost::future do it? Has anybody done so?

... 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. 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. Thanks, Volodya