How to set properly a Win DLL callback ?

[binbinhfr]

Hi,

 

I am trying to receive MIDI messages from a MIDI device. I can open it and send out MIDI messages, but I have more problems to receive MIDI messages.

It is based on events, and I have problem interfacing with the window API.

 

Basically I have 2 functions :

 

midiInOpen (that opens for reception, with a reference to a callback function that I must provide (using the CALLBACK_FUNCTION flag)

https://docs.microsoft.com/en-us/previous-versions/ms711610(v=vs.85)

 

and the callback function itself, midiInProc

https://docs.microsoft.com/en-us/previous-versions/ms711612(v=vs.85)

(I wonder what is this function infact, because I have to write my own... is it a template ?)

 

So how to write my own MidInProc, and how to declare it properly in the midiInOpen call ???

 

Here is what I wrote but it is not working, even though the midiInOpen returns no error (so the device is opened, but the callback does not give any result when MIDI data is coming)....

 

So I wonder if it's the right way to use DllCallbackRegister and DLLCallbackGetPtr, and if I understood the params declaration... Especially in my MidiWinProc2 definition, where finally I do not give any type/size to these params... But I suppose it is the role of DllCallbackRegister  ?

 

global $cbHandle = DllCallbackRegister("MidiWinProc2", "int", "int;uint;dword_ptr;dword_ptr;dword_ptr")
$iRet = _MidiIn_Open($nMidiInDevice, DllCallbackGetPtr($cbHandle), 0, BitOR($CALLBACK_FUNCTION, $MIDI_IO_STATUS))

Func MidiWinProc2($hMidiIn,$wMsg,$dwInstance,$dwParam1,$dwParam2)
  debug("midi in 2")
EndFunc

Func _MidiIn_Open($uDeviceID, $dwCallback, $dwCallbackInstance, $dwFlags)
    Local $aResult = DllCall($MIDI_WinMM_DLL,"int","midiInOpen","int*", 0,"uint_ptr",$uDeviceID,"dword_ptr",$dwCallback,"dword_ptr",$dwCallbackInstance,"dword",$dwFlags)

    If @error Or Not IsArray($aResult) Then Return SetError(1, 1, False)

    If $aResult[0] = $MMSYSERR_NOERROR Then
        Return 1
    ElseIf $aResult[0] = $MMSYSERR_ALLOCATED Then
        Return SetError(1,1,0)
    ElseIf $aResult[0] = $MMSYSERR_BADDEVICEID Then
        Return SetError(2,2,0)
    ElseIf $aResult[0] = $MMSYSERR_INVALFLAG Then
        Return SetError(3,3,0)
    ElseIf $aResult[0] = $MMSYSERR_INVALPARAM Then
        Return SetError(4,4,0)
    ElseIf $aResult[0] = $MMSYSERR_NOMEM Then
        Return SetError(5,5,0)
    Else
        Return SetError(6,6,0)
    EndIf
EndFunc ;

Thanks for your help

[Danyfirex]

Hello It looks right. just change MidiWinProc2 return value to "none"

 

Saludos