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

Le 09/10/15 15:02, Mikael Olenfalk a écrit :

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?

Thanks, Volodya

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. Right.

I haven't really use this stuff, I have been playing with it in order to find out how to combine boost::asio::io_service and boost::future/async, to no avail sadly.

/M

[1] it is guarded by a macro which I cannot find in the docs: BOOST_THREAD_PROVIDES_EXECUTORS Or BOOST_THREAD_VERSION 4

[2] http://www.boost.org/doc/libs/1_59_0/doc/html/thread/synchronization.html#th...

[3] the doc specify an overload then(Scheduler& S) Could you point me where exactly you can fin this?

The doc says template |future| http://www.boost.org/doc/libs/1_59_0/doc/html/thread/synchronization.html#th...::type> then(S& scheduler, F&& func) const; // EXTENSION

but the code looks like this:

#ifdef BOOST_THREAD_PROVIDES_EXECUTORS template inline BOOST_THREAD_FUTURE::type> then(Ex& ex, BOOST_THREAD_FWD_REF(F) func); // EXTENSION #endif

Vicente