C / C++ / MFC

int WasLaunchedInNTDebugger(void) {
	long *data;
	int ret=0;
	// When some debug flags are set on the heap, NT clears
	// the allocated memory with 0xbaadf00d, so we check
	// this to see if we were launched in a debugger
	data = HeapAlloc(GetProcessHeap(), 0, 8);
	if (*data == 0xbaadf00d) {
		ret=1;
	}
	HeapFree(GetProcessHeap(), 0, data);
	return ret;

}

void disableRtlHeapChecking(HANDLE heap) {
	extern HANDLE _crtheap;
	// This is dependent on the current implementation
	// of the XP (and 2K and NT?) heap which stores a
	// number of flags 16 bytes into the heap, and
	// checks the bitmask 0x7D030F60 when deciding
	// whether or not to clear the memory with 0xbaadf00d,
	// so, we're clearing all of the bits that may cause
	// the clearing to happen
	if (heap == NULL)
		heap = _crtheap;
	if (WasLaunchedInNTDebugger()) {
		// This assert is basically because these 2
		// values are the only valuse I saw, if there
		// are any values for these flags, they might
		// mean something special (or a different OS)
		// and we should take a closer look to see if
		// we're clearing anything important. 
		assert(*((long*)heap + 4) == 0x40000061 ||
			*((long*)heap + 4) == 0x40000060);
		// Clear the bad bits!
		*((long*)heap + 4) &= ~0x7D030F60;
	}
}