C++ Error Handling by TheNullz + Ghoul

Handler.cpp

// #include "GhoulTrainer.h"

#define AllocateBuffer(len) \
	new TCHAR[##len]

#ifndef Error
#define Error(func) \
	HandleError(TEXT(#func), TEXT(__FILE__), __LINE__)
#endif

// myCppFile.cpp

LPCTSTR lpFormatStr = "File: %s, Line: %d\n%s";

VOID HandleError (
	__in LPCTSTR lpProcName,
	__in LPCTSTR lpSourceFile,
	__in INT iLine
)
{
	HWND hWnd = GetDesktopWindow();
	DWORD dwMessageIdentifier = GetLastError();

	SIZE_T nStrSize = 1024;
	LPTSTR lpStrBuf = AllocateBuffer(nStrSize);

	__try {
		ZeroMemory(lpStrBuf, nStrSize);

		if (dwMessageIdentifier != NO_ERROR) {
			LPVOID lpvErrStrBuffer = NULL;

			if (FormatMessage(FORMAT_MESSAGE_ALLOCATE_BUFFER | FORMAT_MESSAGE_FROM_SYSTEM | FORMAT_MESSAGE_IGNORE_INSERTS, NULL, dwMessageIdentifier, MAKELANGID(LANG_NEUTRAL, SUBLANG_DEFAULT), (LPTSTR)&lpvErrStrBuffer, 0, NULL) == 0) {
				lpvErrStrBuffer = "An unknown error has occured.";
			}

			if (SUCCEEDED(sprintf_s(lpStrBuf, nStrSize, lpFormatStr, lpProcName, lpSourceFile, iLine, lpvErrStrBuffer))) {
				MessageBox(hWnd, lpStrBuf, "Internal Error", MB_ICONERROR | MB_OK | MB_SETFOREGROUND | MB_TOPMOST);
			}

			if (lpvErrStrBuffer != NULL) {
				LocalFree(reinterpret_cast<HLOCAL>(lpvErrStrBuffer));
			}
		} else if (errno != NULL) {
			LPTSTR lpvErrStrBuffer = AllocateBuffer(nStrSize);

			ZeroMemory(lpvErrStrBuffer, nStrSize);

			if (!_tcserror_s(lpvErrStrBuffer, nStrSize, errno)) {
				if (SUCCEEDED(sprintf_s(lpStrBuf, nStrSize, lpFormatStr, lpProcName, lpSourceFile, iLine, lpvErrStrBuffer))) {
					MessageBox(hWnd, lpStrBuf, "Internal Error", MB_ICONERROR | MB_OK | MB_SETFOREGROUND | MB_TOPMOST);
				}
			}

			delete [] lpvErrStrBuffer;
		}
	} __finally {
		delete [] lpStrBuf;
	}
}