IMAPI2: cannot finish the burn process

Hi, I'm trying to use IWriteEngine2 of IMAPI2 to write a single sector to a disc at LBA 0. Everything goes fine until the very end - when it's supposed to stop burning, the disc keeps spinning and the device is locked. I can't open the tray without doing a restart. In fact, WriteSection() returns S_OK, indicating that data must've been written, although the medium (CD-RW) remains blank afterwards (checked with hex editor).

Every call to the COM methods returns S_OK (this is what Assert() checks for), see excerpt below.

Code:

	CoInitialize(NULL);

	IWriteEngine2* writeEngine;
	Assert(CoCreateInstance(__uuidof(MsftWriteEngine2), NULL, CLSCTX_ALL,
		__uuidof(IWriteEngine2), (void**)&writeEngine));
	
	IDiscRecorder2* discRecorder;
	Assert(CoCreateInstance(__uuidof(MsftDiscRecorder2), NULL, CLSCTX_ALL,
		__uuidof(IDiscRecorder2), (void**)&discRecorder));

	IDiscMaster2* discMaster;
	Assert(CoCreateInstance(__uuidof(MsftDiscMaster2), NULL, CLSCTX_ALL,
		__uuidof(IDiscMaster2), (void**)&discMaster));

	BSTR uniqueID;
	long numDevices = 0;
	Assert(discMaster->get_Count(&numDevices));
	for(int i = 0; i < 100; i++)
		if(discMaster->get_Item(i, &uniqueID) == S_OK) break;
	Assert(discRecorder->InitializeDiscRecorder(uniqueID));
	Assert(discRecorder->AcquireExclusiveAccess(VARIANT_TRUE, SysAllocString(L"abcd")));
	Assert(writeEngine->put_Recorder((IDiscRecorder2Ex*)discRecorder));
	Assert(writeEngine->put_BytesPerSector(2048));
	Assert(writeEngine->put_StartingSectorsPerSecond(-1));
	Assert(writeEngine->put_EndingSectorsPerSecond(-1));

	IStream* patternStream;
	patternStream = SHCreateMemStream(pattern, 2048); //pattern is a valid pointer to 2048 bytes of memory

	Assert(writeEngine->WriteSection(patternStream, 0, 1)); //after burning this returns S_OK

	Assert(discRecorder->ReleaseExclusiveAccess());

I've tried reading the stream, which works fine, so it shouldn't be a problem with IStream. The reason I'm using IWriteEngine2 is that data will be generated "on the fly" and should not be written in the conventional data CD format, but raw.

Let me know of any ideas to fix this. Thanks!

Originally Posted by Overlord

Code:

	Assert(writeEngine->put_Recorder((IDiscRecorder2Ex*)discRecorder));

discRecorder is an IDiscRecorder2* not an IDiscRecorder2Ex*. These are about the same as a HWND and a HBITMAP.

To get an instance of this interface (IDiscRecorder2Ex), create an instance of the IDiscRecorder2 interface and then call the IDiscRecorder2::QueryInterface method to retrieve the IDiscRecorder2Ex interface.

This isn't optional.

Also:

Code:

Assert(discRecorder->AcquireExclusiveAccess(VARIANT_TRUE, SysAllocString(L"abcd")/* mem leak */));

Thanks for replying, adeyblue, but it still doesn't work - the diode on the drive keeps blinking and it won't open. In addition to preventing the mem leak, this is how I acquired the new interface:

Code:

	IDiscRecorder2Ex* discRecorder;
	discRecorderNoEx->QueryInterface(IID_IDiscRecorder2Ex, (void**)&discRecorder);
	Assert(writeEngine->put_Recorder(discRecorder));

Have you worked with these interfaces? Maybe you've got some examples I could verify my code against?