[2005] C to VB.Net translation experts only please

[agent]

I'm trying to convert a C structure that include function pointer into a VB.Net structure that contain delegates. (Only .Net 2.0 and 3.0 users should attempt this.) When I call a function in an unmanaged dll that fills the structure, I get the following error (nontrapable exception):

InvalidFunctionPointerInDelegate was detected
Message: Invalid function pointer 0xb6390c91 was passed into the runtime to be converted to a delegate. Passing in invalid function pointers to be converted to delegates can cause crashes, corruption or data loss.

Can anybody tell me how I got my delegate definitions or signatures messed up?

Original structure:

typedef struct 
{
	int version;				// module type (IN_VER)
	char *description;			// description of module, with version string

	HWND hMainWindow;			// winamp's main window (filled in by winamp)
	HINSTANCE hDllInstance;		// DLL instance handle (Also filled in by winamp)

	char *FileExtensions;		// "mp3\0Layer 3 MPEG\0mp2\0Layer 2 MPEG\0mpg\0Layer 1 MPEG\0"
								// May be altered from Config, so the user can select what they want
	
	int is_seekable;			// is this stream seekable? 
	int UsesOutputPlug;			// does this plug-in use the output plug-ins? (musn't ever change, ever :)

	void (*Config)(HWND hwndParent); // configuration dialog
	void (*About)(HWND hwndParent);  // about dialog

	void (*Init)();				// called at program init
	void (*Quit)();				// called at program quit

	void (*GetFileInfo)(char *file, char *title, int *length_in_ms); // if file == NULL, current playing is used
	int (*InfoBox)(char *file, HWND hwndParent);
	
	int (*IsOurFile)(char *fn);	// called before extension checks, to allow detection of mms://, etc
	// playback stuff
	int (*Play)(char *fn);		// return zero on success, -1 on file-not-found, some other value on other (stopping winamp) error
	void (*Pause)();			// pause stream
	void (*UnPause)();			// unpause stream
	int (*IsPaused)();			// ispaused? return 1 if paused, 0 if not
	void (*Stop)();				// stop (unload) stream

	// time stuff
	int (*GetLength)();			// get length in ms
	int (*GetOutputTime)();		// returns current output time in ms. (usually returns outMod->GetOutputTime()
	void (*SetOutputTime)(int time_in_ms);	// seeks to point in stream (in ms). Usually you signal yoru thread to seek, which seeks and calls outMod->Flush()..

	// volume stuff
	void (*SetVolume)(int volume);	// from 0 to 255.. usually just call outMod->SetVolume
	void (*SetPan)(int pan);	// from -127 to 127.. usually just call outMod->SetPan
	
	// in-window builtin vis stuff

	void (*SAVSAInit)(int maxlatency_in_ms, int srate);		// call once in Play(). maxlatency_in_ms should be the value returned from outMod->Open()
	// call after opening audio device with max latency in ms and samplerate
	void (*SAVSADeInit)();	// call in Stop()


	// simple vis supplying mode
	void (*SAAddPCMData)(void *PCMData, int nch, int bps, int timestamp); 
											// sets the spec data directly from PCM data
											// quick and easy way to get vis working :)
											// needs at least 576 samples :)

	// advanced vis supplying mode, only use if you're cool. Use SAAddPCMData for most stuff.
	int (*SAGetMode)();		// gets csa (the current type (4=ws,2=osc,1=spec))
							// use when calling SAAdd()
	void (*SAAdd)(void *data, int timestamp, int csa); // sets the spec data, filled in by winamp


	// vis stuff (plug-in)
	// simple vis supplying mode
	void (*VSAAddPCMData)(void *PCMData, int nch, int bps, int timestamp); // sets the vis data directly from PCM data
											// quick and easy way to get vis working :)
											// needs at least 576 samples :)

	// advanced vis supplying mode, only use if you're cool. Use VSAAddPCMData for most stuff.
	int (*VSAGetMode)(int *specNch, int *waveNch); // use to figure out what to give to VSAAdd
	void (*VSAAdd)(void *data, int timestamp); // filled in by winamp, called by plug-in


	// call this in Play() to tell the vis plug-ins the current output params. 
	void (*VSASetInfo)(int nch, int srate);


	// dsp plug-in processing: 
	// (filled in by winamp, called by input plug)

	// returns 1 if active (which means that the number of samples returned by dsp_dosamples
	// could be greater than went in.. Use it to estimate if you'll have enough room in the
	// output buffer
	int (*dsp_isactive)(); 

	// returns number of samples to output. This can be as much as twice numsamples. 
	// be sure to allocate enough buffer for samples, then.
	int (*dsp_dosamples)(short int *samples, int numsamples, int bps, int nch, int srate);


	// eq stuff
	void (*EQSet)(int on, char data[10], int preamp); // 0-64 each, 31 is +0, 0 is +12, 63 is -12. Do nothing to ignore.

	// info setting (filled in by winamp)
	void (*SetInfo)(int bitrate, int srate, int stereo, int synched); // if -1, changes ignored? :)

	Out_Module *outMod; // filled in by winamp, optionally used :)
} In_Module;

Translated to vb.net

<StructLayout(LayoutKind.Sequential)> _
    Structure InModule
        Public version As Integer
        Public description As String
 
        Public hMainWindow As IntPtr
        Public hDllInstance As IntPtr
 
        Public FileExtensions As String
 
        Public is_seekable As Integer
        Public UsesOutputPlug As Integer
 
        Public Delegate Sub ConfigPTR(ByVal hwndParent As IntPtr)
        Public Config As ConfigPTR
 
        Public Delegate Sub AboutPTR(ByVal hwndParent As IntPtr)
        Public About As AboutPTR
 
        Public Delegate Sub InitPTR()
        Public Init As InitPTR
 
        Public Delegate Sub QuitPTR()
        Public Quit As QuitPTR
 
        Public Delegate Sub GetFileInfoPTR(ByRef file As String, ByRef title As String, ByRef lenght_in_ms As Integer)
        Public GetFileInfo As GetFileInfoPTR
 
        Public Delegate Function InfoBoxPTR(ByRef file As String, ByVal hwndParent As IntPtr) As Integer
        Public InfoBox As InfoBoxPTR
 
        Public Delegate Function IsOurFilePTR(ByRef fn As String) As Integer
        Public IsOurFile As IsOurFilePTR
 
        '//Playback stuff
        Public Delegate Function PlayPTR(ByRef fn As String) As Integer
        Public Play As PlayPTR
 
        Public Delegate Sub PausePTR()
        Public Pause As PausePTR
 
        Public Delegate Sub UnPausePTR()
        Public UnPause As UnPausePTR
 
        Public Delegate Function IsPausedPTR() As Integer
        Public IsPaused As IsPausedPTR
 
        Public Delegate Sub StopPTR()
        Public [Stop] As StopPTR
 
        '//Time stuff
        Public Delegate Function GetLengthPTR() As Integer
        Public GetLength As GetLengthPTR
 
        Public Delegate Function GetOutputTimePTR() As Integer
        Public GetOutputTime As GetOutputTimePTR
 
        Public Delegate Sub SetOutputTimePTR(ByVal time_in_ms As Integer)
        Public SetOutputTime As SetOutputTimePTR
 
        '//Volume stuff
        Public Delegate Sub SetVolumePTR(ByVal volume As Integer)
        Public SetVolume As SetVolumePTR
 
        Public Delegate Sub SetPanPTR(ByVal pan As Integer)
        Public SetPan As SetPanPTR
 
        '//In-window builtin vis stuff
        Public Delegate Sub SAVSAInitPTR(ByVal maxlatency_in_ms As Integer, ByVal srate As Integer)
        Public SAVSAInit As SAVSAInitPTR
 
        Public Delegate Sub SAVSADeInitPTR()
        Public SAVSADeInit As SAVSADeInitPTR
 
        '//Simple vis supplying mode
        Public Delegate Sub SAAddPCMDataPTR(ByRef PCMData As Byte(), ByVal nch As Integer, ByVal bps As Integer, ByVal timestamp As Integer)
        Public SAAddPCMData As SAAddPCMDataPTR
 
        '//Advanced vis supplying mode
        Public Delegate Function SAGetModePTR() As Integer
        Public SAGetMode As SAGetModePTR
 
        Public Delegate Sub SAAddPTR(ByRef data As Byte(), ByVal timestamp As Integer, ByVal csa As Integer)
        Public SAAdd As SAAddPTR
 
        '//vis stuff (plug-in)
        '//simple vis supplying mode
        Public Delegate Sub VSAAddPCMDataPTR(ByRef PCMData As Byte(), ByVal nch As Integer, ByVal bps As Integer, ByVal timestamp As Integer)
        Public VSAAddPCMData As VSAAddPCMDataPTR
 
        '//advanced vis supplying mode
        Public Delegate Function VSAGetModePTR(ByRef specNch As Integer, ByRef waveNch As Integer) As Integer
        Public VSAGetMode As VSAGetModePTR
 
        Public Delegate Sub VSAAddPTR(ByRef data As Byte(), ByVal timestamp As Integer)
        Public VSAAdd As VSAAddPTR
 
        Public Delegate Sub VSASetInfoPTR(ByVal nch As Integer, ByVal srate As Integer)
        Public VSASetInfo As VSASetInfoPTR
 
        '//dsp plug-in processing: 
        '//(filled in by winamp, called by input plug)
 
        Public Delegate Function dsp_isactivePTR() As Integer
        Public dsp_isactive As dsp_isactivePTR
 
        Public Delegate Function dsp_dosamplesPTR(ByRef samples As Short, ByVal numsamples As Integer, ByVal bps As Integer, ByVal nch As Integer, ByVal srate As Integer) As Integer
        Public dsp_dosamples As dsp_dosamplesPTR
 
        '//eq stuff
        Public Delegate Sub EQSetPTR(ByVal [on] As Integer, ByVal data As Byte(), ByVal preamp As Integer) 'data is limited to 10 elements
        Public EQSet As EQSetPTR
 
        '//info setting
        Public Delegate Sub SetInfoPTR(ByVal bitrate As Integer, ByVal srate As Integer, ByVal stereo As Integer, ByVal synched As Integer)
        Public SetInfo As SetInfoPTR
 
        Public Out_Mod As WinampOutputPlugin.OutModule
    End Structure

Let me know if more information is required.