CODEWITHSUNDEEP
c++
Fratink
Fratink

Reputation: 124

_beginthreadex with member functions

I'm not sure I'm going about this in the right way, but I'm working with member functions and threads in C++ and Visual Studio 2013.

Other answers I've found said that I must cast my member function as a static function, which allows me to create that thread. The problem I have is that I cannot call any other member functions that also aren't static.

Here's an excerpt of my code:

//Start the thread for the receive function
    receiveMessageHandle = (HANDLE)_beginthreadex(0, 0, &foo::receiveMessageThread, (void*)0, 0, 0);
    return 0;
}

unsigned int __stdcall foo::receiveMessageThread(void *threadToStart)
{
    foo::receiveMessages(); //Non-static member function!
    return 0;
}

The non-static member function receiveMessageThread can't be cast as a static member variable either since it uses private member variables.

Any ideas? Is there a better way to begin a thread here?

Upvotes: 3

Views: 4590

Answers (1)

Nikolay
Nikolay

Reputation: 12245

Normally this is solved by passing "this" object (i.e. instance) as a parameter to the static function:

class foo
{
public:
    void startTheThread()
    {
        //Start the thread for the receive function (note "this")
        receiveMessageHandle = 
            _beginthreadex(0, 0, &foo::receiveMessageThread, this, 0, 0);
    }
private:
    void receiveMessages()
    {
    }

    static unsigned int __stdcall receiveMessageThread(void *p_this)
    {
        foo* p_foo = static_cast<foo*>(p_this);
        p_foo->receiveMessages(); // Non-static member function!
        return 0;
    }
    unsigned int receiveMessageHandle;
};

// somewhere
foo* the_foo = ...
the_foo->startTheThread();

Upvotes: 3

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