[boost] [threadpool] draft n2276 - interrupting tasks

Subject: [boost] [threadpool] draft n2276 - interrupting tasks
From: k-oli_at_[hidden]
Date: 2008-11-22 11:38:54

Hello,

the draft specifies that the threapool::submit() function returns a future 
object in order to retrieve the result of the submited task.

What about task cancelation/interruption?

Instead returning a future the pool could return a task< R > object which 
contains a future< R > (access over R task< R >::get()) and interruption 
routines.

boost.threadpool in the boost vault implements somthing like:

task< R > threadpool::submit(...);

template< typename R >
class task
{
...
        // interrupt task and return immediatly
        void interrupt();

        // interrupt task and wait till it's finished
        void interrupt_and_wait();

        // interrupt task and wait a certain time till it's finished or timeout
        template< typename TimeDuration >
        void interrupt_and_wait( TimeDuration const& td);

        // interrupt task and wait to a specific system time till it's finished or 
timeout
        void interrupt_and_wait( system_time const& st);

        bool interrupt_requested();

        R get()
        { return impl_fut_->get(); }
        bool ready() const
        { return impl_fut_->ready(); }

        bool has_value() const;

        bool has_exception() const;
};

Following Herb Sutters sugestions the  submited task must be cooperative 
(contain interruption_point).

What do you think? Should/Could it be added to the draft?

regards,
Oliver
        { return impl_fut_->has_exception(); }