Re: [Boost-users] Problems with boost::coroutines with lambda captures

Subject: Re: [Boost-users] Problems with boost::coroutines with lambda captures
From: Tamas.Ruszkai_at_[hidden]
Date: 2015-09-17 02:49:32

Thanks Mikhail, it solved the problem!
Such a trivial error... :-(
Actually it was the pull_type, not the
push_type, but I guess this is also what you have meant.

In the updated version I store also
the function object inside the generator.

        template
<typename
TOutput>
        using
GeneratorBlockYield
= typename
boost::coroutines::asymmetric_coroutine<TOutput>::push_type;

        template<typename
TOutput>
        class
GeneratorBlockEnumerator
: public
IEnumerator<TOutput>
        {
        public:
           
    explicit
GeneratorBlockEnumerator(std::function<void(GeneratorBlockYield<TOutput>&)>
generator)
           
            : _firstMoveNextCall(true)
           
            , _generatorFunctor(generator)
           
            , _generatorPuller(_generatorFunctor)
           
    {
           
    }

           
    ~GeneratorBlockEnumerator() override
= default;

           
    bool
MoveNext() override
           
    {
           
            auto
generatorNotFinished = static_cast<bool>(_generatorPuller);
           
            if
(!generatorNotFinished)
           
               
    return
false;

           
            if
(_firstMoveNextCall)
           
            {
           
               
    _firstMoveNextCall
= false;
           
            }
           
            else
           
            {
           
               
    _generatorPuller();
           
            }

           
            generatorNotFinished
= static_cast<bool>(_generatorPuller);
           
            return
generatorNotFinished;
           
    }

           
    TOutput
Current() const
override
           
    {
           
            return
_generatorPuller.get();
           
    }

        private:
           
    bool
_firstMoveNextCall;
           
    std::function<void(GeneratorBlockYield<TOutput>&)>
_generatorFunctor;
           
    typename
boost::coroutines::asymmetric_coroutine<TOutput>::pull_type
_generatorPuller;
        };




From:      
 Mikhail Strelnikov
<[e-mail]>
To:      
 [e-mail]
Date:      
 17.09.2015 04:24
Subject:    
   [Boost-users]
Problems with boost::coroutines with lambda captures
Sent by:    
   "Boost-users"
<[e-mail]>



> Sumamry: somehow the captured smart pointer gets
destroyed+corrupted
> when I yield from the coroutine, but the local copy
survives. When I use

GeneratorBlockEnumerator gets parameter (std::function)
by value (temporary function gets created before constructor and destroyed
right after). Then this temporary function passed by reference to push_type.
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