About waveinopen

minihotto

Hello, I have a question about callback function. My code is waveInOpen(&hWav,0, &wfx,WaveInCallback ,0, CALLBACK_FUNCTION); But it comes some problems, the error message is error C3867: 'p2p::Form1::WaveInCallback': function call missing argument list; use '&p2p::Form1::WaveInCallback' to create a pointer to member I dont realize what happened. Can anybody solve this question for me? Jane

Nishad S

This error happens when you tried to take the address of a member function without qualifying the member function with its class name and the address-of operator. Can you show the callback function declaration?

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minihotto

OK. void CALLBACK WaveInCallback(HWAVEIN hw, UINT uMsg, DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD dwParam2) { waveInAddBuffer(hw, (WAVEHDR*)dwParam1, sizeof(WAVEHDR)); } I create it in the From.h. But I don't know where to allocate it.

Nishad S

Isn't it a static function? AFAIK it should be static function. Also I found a mismatch with the documentation in MSDN. See... void CALLBACK waveInProc( HWAVEIN hwi, UINT uMsg, DWORD dwInstance, DWORD dwParam1, DWORD dwParam2 ); You are using DWORD_PTR instead of DWORD. But I am not sure about this :(

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minihotto

Appreciate for ur reply. But it's still same.

Nishad S

Try to cast like waveInOpen(&hWav,0, &wfx,(DWORD_PTR)WaveInCallback ,0, CALLBACK_FUNCTION);

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minihotto

It comes other errors.@@ 1.error C3374: can't take address of 'p2p::Form1::WaveInCallback' unless creating delegate instance 2.error C2440: 'type cast' : cannot convert from 'void (__clrcall p2p::Form1::* )(HWAVEIN,UINT,DWORD_PTR,DWORD_PTR,DWORD)' to 'DWORD_PTR'

Nishad S

Please show me the declaration of the callback function. Not in the cpp but inside the class in header file.

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David Crow

NS17 wrote:

Please show me the declaration of the callback function.

It's declared in mmsystem.h:

void CALLBACK waveInProc(
HWAVEIN hwi,
UINT uMsg,
DWORD dwInstance,
DWORD dwParam1,
DWORD dwParam2
);

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minihotto

public ref class Form1 : public System::Windows::Forms::Form { public: Form1(void) { InitializeComponent(); // //TODO: Add the constructor code here // } int call_id; void CALLBACK WaveInCallback(HWAVEIN hw, UINT uMsg,DWORD_PTR dwInstance, DWORD_PTR dwParam1, DWORD dwParam2) { WAVEHDR* curhdr = (WAVEHDR*)dwParam1; waveInAddBuffer(hw, curhdr, sizeof(WAVEHDR)); } ............ I put in the class form1

jhwurmbach

minihotto wrote:

public ref class Form1 : public System::Windows::Forms::Form

You very certainly wanted to ask that in the "Managed C++"-Forum?!? :^)

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Hamid Taebi

I agree ask on the correct forum.

Nishad S

I am not sure about this coding. :( In C++, it should be static declaration. Try to make it static function.

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Nishad S

:)

DavidCrow wrote:

It's declared in mmsystem.h:

I meant how he declared the the function to use as callback.

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