How can I create a debug console for GUI app using pure WIN32 API calls

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I'm playing around with creating a debug console on for a WIN32 GUI app and I'm trying to do it a different way and by the life of me I cannot get this working, its such a simple thing but it's driving me crazy. I know this has been asked a million times before and the general way and what I have been using is this:

AllocConsole();

freopen("CON", "r", stdin);
freopen("CON", "w", stdout);
freopen("CON", "w", stderr);

or also

OutputDebugString(TEXT("blah, blah blah");

I guess too much free time/boredom/curiosity, or some strange will to do things the hardest way possible, I wanted to try doing it differently with just pure WIN32 calls with AllocConsole, CreateFile, SetStdHandle. No matter how much googling or searching through MSDN, I cant get this to work correctly. All the functions return successful and console opens up on the screen, but no input/ouput.

What I have tried:

AllocConsole();

HANDLE hConsoleSTDIN = CreateFile("CONIN$", GENERIC_READ | GENERIC_WRITE,
                                  FILE_SHARE_READ, 0, OPEN_EXISTING, 0, 0);

SetStdHandle(STD_INPUT_HANDLE, hConsoleSTDIN);

HANDLE hConsoleSTDOUT = CreateFile("CONOUT$", GENERIC_READ | GENERIC_WRITE,
                                   FILE_SHARE_WRITE, 0, OPEN_EXISTING, 0, 0);

SetStdHandle(STD_OUTPUT_HANDLE, hConsoleSTDOUT);

if I printf() or std::cout, nothing is displayed.

Any help would be great.
Thanks
Matt

Posted 8-Feb-19 2:32am

Matt386

Updated 15-Apr-19 17:47pm

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11917640 Member 16-Apr-19 1:04am

You can change the /SUBSYSTEM parameter from Windows to Console (if this causes linker error, change also /ENTRY parameter). Or just use OutputDebugString + DebugView https://docs.microsoft.com/en-us/sysinternals/downloads/debugview

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Michael Haephrati · Answer 1 · 2019-04-15T17:47:00

I use a Console window to debug all of my applications, with or without GUI.
I use pure Win32 API in most of the cases.
See This article[^]
Not only that it possible but you can set colors and font styles.
First, you call:

#include <conio.h>
HANDLE hConsole = GetStdHandle(STD_OUTPUT_HANDLE);

To set the text color, I use:

inline void setcolor(int textcol, int backcol)
{
	if ((textcol % 16) == (backcol % 16))textcol++;
	textcol %= 16; backcol %= 16;
	unsigned short wAttributes = ((unsigned)backcol << 4) | (unsigned)textcol;
	CONSOLE_SCREEN_BUFFER_INFO csbi;
	SetConsoleTextAttribute(hConsole, wAttributes);
}

Then, just use wprintf() to display the text.
If you wish to clear the display area, just call:

system("cls");

Also refresh the display by calling:

void refresh()
{
	HWND hwnd = FindWindowEx(NULL, NULL, L"CabinetWClass", NULL);
	while (hwnd != NULL)
	{
		PostMessage(hwnd, WM_COMMAND, 41504, 0);
		hwnd = FindWindowEx(NULL, hwnd, L"CabinetWClass", NULL);
	}
}

Richard MacCutchan · Answer 2 · 2019-02-08T03:17:00

Solution 1

See c++ - AllocConsole() not displaying cout - Stack Overflow[^]

Posted 8-Feb-19 3:17am

Richard MacCutchan

How can I create a debug console for GUI app using pure WIN32 API calls

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How can I create a debug console for GUI app using pure WIN32 API calls

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