C++ / SDL Debugging with console window - c++

Question

I am playing around with some OpenGL, using SDL to handle the window / input etc. Currently I am displaying any information I want to see to a HUD. Well, this is getting over-cumbersome, and I was wondering if there is a simple way to open up a separate console window to report this information to me. I am still new to C++ so go easy on me if this is an obvious one.

Answer 1

The following code is for Windows. I always find it handy to keep around the ability to create a console window on demand:
int hConHandle;
intptr_t lStdHandle;
CONSOLE_SCREEN_BUFFER_INFO coninfo;
FILE *fp;
// allocate a console for this app
AllocConsole();
// set the screen buffer to be big enough to let us scroll text
GetConsoleScreenBufferInfo(GetStdHandle(STD_OUTPUT_HANDLE), &coninfo);
coninfo.dwSize.Y = 500;
SetConsoleScreenBufferSize(GetStdHandle(STD_OUTPUT_HANDLE), coninfo.dwSize);
// redirect unbuffered STDOUT to the console
lStdHandle = (intptr_t)GetStdHandle(STD_OUTPUT_HANDLE);
hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
fp = _fdopen( hConHandle, "w" );
*stdout = *fp;
setvbuf( stdout, NULL, _IONBF, 0 );
// redirect unbuffered STDIN to the console
lStdHandle = (intptr_t)GetStdHandle(STD_INPUT_HANDLE);
hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
fp = _fdopen( hConHandle, "r" );
*stdin = *fp;
setvbuf( stdin, NULL, _IONBF, 0 );
// redirect unbuffered STDERR to the console
lStdHandle = (intptr_t)GetStdHandle(STD_ERROR_HANDLE);
hConHandle = _open_osfhandle(lStdHandle, _O_TEXT);
fp = _fdopen( hConHandle, "w" );
*stderr = *fp;
setvbuf( stderr, NULL, _IONBF, 0 );
// make cout, wcout, cin, wcin, wcerr, cerr, wclog and clog point to console as well
std::ios::sync_with_stdio();
//Keep our window in focus
SetForegroundWindow(m_hWnd); // Slightly Higher Priority
SetFocus(m_hWnd); // Sets Keyboard Focus To The Window
This code assumes that the HWND is in a variable called m_hWnd; it's copied from a class wrapper I use. How you get the HWND from SDL is up to you, however.
To free the console, call this:
FreeConsole();
AllocConsole and FreeConsole are Win32 API functions.

Answer 2

In Linker -> System in your project's properties, check that the SubSystem is "Console (/SUBSYSTEM:CONSOLE)". That causes a separate console window to be brought up when you run your program. If your current entry point isn't main, then you'll need to change it to that if you do this though.

Answer 3

If you're running from a command line and use printf() you should see messages logged out to your terminal window. Otherwise you could log to a file and use tail -f on *nix style boxes to view the output as it appears.
What environment are you using? Most IDEs will show this output in their debug output windows as well.