Programming Forums > Application Development > C++

jayme · Apr 10th, 2006, 10:42 PM

I need to create a thread inside a class that allows the programmer to access the member functions. The way I declare my thread, though, I don't think it's possible to create a "member thread", or whatever, how I want to. Here's how I initialize the thread

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DWORD WINAPI RecvThread(LPVOID lpParameter);

Whenever I try to use an access member scopre like so:

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DWORD WINAPI Client::RecvThread(LPVOID lpParameter)
{
   //do stuff
}

I'm told I can't do that. Does anyone have a clue how I would create a class thread?

The only other solution I've had was to create the class object globally so that the thread could receive while another function was sending messages, which everyone knows, declaring globally is wrong.

The Dark · Apr 11th, 2006, 12:32 AM

Use a "normal" function as the thread function, but have it immediately call a member function in your class to do the work.
Pass the class object in the lpParameter value and cast it to the class
E.g.

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class MyThreadClass
{
  public:
    DWORD RecvThread();
  private:
    // blah blah
}

DWORD Client::RecvThread()
{
   //do stuff
}

DWORD WINAPI RecvThread(LPVOID lpParameter)
{
   MyThreadClass *ptr = static_cast<MyThreadClass *>(lpParameter);
   return ptr->RecvThread;
}

If you don't care about the return value from the member function RecvThread, you can make it void and make the wrapper function return 0 (or whatever).

Edit: You could also make the wrapper function a static member of the class, whatever floats your boat.

grumpy · Apr 11th, 2006, 4:23 AM

Minor correction to Dark's example. The thread function should be something like;

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DWORD WINAPI RecvThread(LPVOID lpParameter)
{
   MyThreadClass *ptr = static_cast<MyThreadClass *>(lpParameter);
   return ptr->RecvThread();    // calling a member function, not returning a pointer to member
}

The Dark · Apr 11th, 2006, 5:54 AM

Oops :o

Apr 11th, 2006, 12:32 AM	#2
The Dark Expert Programmer Join Date: Jun 2005 Posts: 893 Rep Power: 4	Use a "normal" function as the thread function, but have it immediately call a member function in your class to do the work. Pass the class object in the lpParameter value and cast it to the class E.g. (Toggle Plain Text) class MyThreadClass { public: DWORD RecvThread(); private: // blah blah } DWORD Client::RecvThread() { //do stuff } DWORD WINAPI RecvThread(LPVOID lpParameter) { MyThreadClass ptr = static_cast<MyThreadClass >(lpParameter); return ptr->RecvThread; } class MyThreadClass { public: DWORD RecvThread(); private: // blah blah } DWORD Client::RecvThread() { //do stuff } DWORD WINAPI RecvThread(LPVOID lpParameter) { MyThreadClass ptr = static_cast<MyThreadClass >(lpParameter); return ptr->RecvThread; } If you don't care about the return value from the member function RecvThread, you can make it void and make the wrapper function return 0 (or whatever). Edit: You could also make the wrapper function a static member of the class, whatever floats your boat.

Apr 11th, 2006, 4:23 AM	#3
grumpy Programming Guru Join Date: Jun 2005 Location: Adelaide, South Australia Posts: 1,260 Rep Power: 5	Minor correction to Dark's example. The thread function should be something like; (Toggle Plain Text) DWORD WINAPI RecvThread(LPVOID lpParameter) { MyThreadClass ptr = static_cast<MyThreadClass >(lpParameter); return ptr->RecvThread(); // calling a member function, not returning a pointer to member } DWORD WINAPI RecvThread(LPVOID lpParameter) { MyThreadClass ptr = static_cast<MyThreadClass >(lpParameter); return ptr->RecvThread(); // calling a member function, not returning a pointer to member }

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Apr 11th, 2006, 5:54 AM	#4
The Dark Expert Programmer Join Date: Jun 2005 Posts: 893 Rep Power: 4	Oops :o

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