C / C++ / MFC

LPTSTR FileHelper::GetFileFullPath( LPWSTR lpwName )
{
	LPTSTR lptFileFullPath;

	DWORD LenInChars = GetCurrentDirectory( 0, NULL );

	++LenInChars; // add 1 for NULL terminator

	LPWSTR lpwFolder;
	lpwFolder = (LPWSTR) malloc( LenInChars * sizeof(TCHAR) );

	if ( lpwFolder == NULL )
	{
		return NULL; // or throw new CIScrewedUpException();
	}

	if ( GetCurrentDirectory( LenInChars, lpwFolder ) != 0 )
	{
		// added 1 for NULL terminator
		LenInChars = (DWORD) ( wcslen( lpwFolder ) + wcslen( lpwName ) + 1 );

		lptFileFullPath = (LPTSTR) malloc( LenInChars * sizeof(TCHAR));

		// Here lptFileFullPath simply evaluates to NULL, showing the ?!
		if ( lptFileFullPath == NULL )
		{
			// prevent memory leak
			free( lpwFolder );
			return NULL;
		}

		// ...the rest of the code stripped off...
	}

	// prevent memory leak
	free( lpwFolder );

	return lptFileFullPath;
}

damir_tk wrote:

1. Why malloc sucks, I don't see any problems with it. New and delete is better when you are creating some objects that have a constructor and a destructor, as they get called automatically, but not if you use malloc. But here I only use strings and string pointers, so why?

damir_tk wrote:

2. I already rewrite the code, to use something like:

lpwFolder = (LPWSTR) malloc( (len + 1) * 2 );

Is it wrong? (Apart from not being elegant :=) ).

3. I use _tcslen instead of wcslen, is it better suited here?

LPTSTR FileHelper::GetFileFullPath( LPCTSTR lpwName )
{
	LPTSTR lptFileFullPath;
	DWORD LenInChars = ::GetCurrentDirectory( 0, NULL );
	++LenInChars; // add 1 for NULL terminator
	LPTSTR lpwFolder = new TCHAR[ LenInChars ];
	if ( lpwFolder == NULL )
	{
		return NULL;
	}
	if ( ::GetCurrentDirectory( LenInChars, lpwFolder ) != 0 )
	{
		// I added 6 like you did before...you may need more chars for backslashes and such
		LenInChars = (DWORD)( _tcslen( lpwFolder ) + _tcslen( lpwName ) + 6 );
		lptFileFullPath = new TCHAR[ LenInChars ];
		if ( lptFileFullPath == NULL )
		{
			// prevent memory leak
			delete[] lpwFolder;
			return NULL;
		}
		// ...the rest of the code stripped off...
	}
	// prevent memory leak
	delete[] lpwFolder;
	return lptFileFullPath;
}

vikas amin wrote:

Vikas Amin
EATON
PUNE

vikas amin wrote:

Can i know u ?

int WINAPI WinMain(HINSTANCE hInst, HINSTANCE, LPSTR, int)
{
    FILE *fp = fopen("C:\\test.txt", "wt");
    fprintf(fp, "Hello, world!\n");
    fclose(fp);

    // just for effect...
    MessageBox(GetActiveWindow(), "Done!", "GUI-less Program", MB_OK);
}

Johpoke wrote:

How should i place that in MS visual c++ in a new win32 console project?