Write debug output to console window

Environment: any MSVC

It's very common that we have to test our program on another machine where the Visual C++ IDE is not installed. So there will be no debug window for output. Logging into a file or keep popping up MessageBoxs are not very practical ways. An easy solution is to show the output strings in a console window.

Put the following code at the beginning of your app file or in a separate file.


#ifdef _DEBUG
    FILE* __fStdOut = NULL;
    HANDLE __hStdOut = NULL;
#endif

// width and height is the size of console window, if you specify fname, 
// the output will also be writton to this file. The file pointer is automatically closed 
// when you close the app
void startConsoleWin(int width=80, int height=25, char* fname = NULL);

void startConsoleWin(int width, int height, char* fname)
{
#ifdef _DEBUG
	AllocConsole();
	SetConsoleTitle("Debug Window");
	__hStdOut = GetStdHandle(STD_OUTPUT_HANDLE);

	COORD co = {width,height};
	SetConsoleScreenBufferSize(__hStdOut, co);

	if(fname)
		__fStdOut = fopen(fname, "w");
#endif
}

// Use wprintf like TRACE0, TRACE1, ... (The arguments are the same as printf)
int wprintf(char *fmt, ...)
{
#ifdef _DEBUG
	char s[300];
	va_list argptr;
	int cnt;

	va_start(argptr, fmt);
	cnt = vsprintf(s, fmt, argptr);
	va_end(argptr);

	DWORD cCharsWritten;

	if(__hStdOut)
		WriteConsole(__hStdOut, s, strlen(s), &cCharsWritten, NULL);

	if(__fStdOut)
		fprintf(__fStdOut, s);

	return(cnt);
#else
	return 0;
#endif
}

In CWinApp::InitInstance() call startConsoleWin() and a console window will popup. Then use wprintf at places where you used to use TRACE. The output strings will then appear in the console window.



Comments

  • There are no comments yet. Be the first to comment!

Leave a Comment
  • Your email address will not be published. All fields are required.

Top White Papers and Webcasts

  • Today's agile organizations pose operations teams with a tremendous challenge: to deploy new releases to production immediately after development and testing is completed. To ensure that applications are deployed successfully, an automatic and transparent process is required. We refer to this process as Zero Touch Deployment™. This white paper reviews two approaches to Zero Touch Deployment--a script-based solution and a release automation platform. The article discusses how each can solve the key …

  • What if you could rapidly grow your business while eliminating the complexity and multiple operating systems, administration and management tools, and security and compliance requirements? See how many good things happen when you standardize on open, flexible infrastructure solutions.

Most Popular Programming Stories

More for Developers

RSS Feeds

Thanks for your registration, follow us on our social networks to keep up-to-date