[AD] Breakpointing an app in the MSVC 6 debugger can get a key to be stuck in Windows 2000

[Andrei Ellman <ae-a-alleg@xxxxxxxxxx>]

The following test program demonstrates a problem with the keyboard 
driver when debugging an app with MSVC 6 under Windows 2000. The program 
is supposed to display a message when the F2 key is held down and clear 
it when it is not held down. However, if I am debugging the program 
using the MSVC 6 debugger and I place a breakpoint on the line that is 
only supposed to be execuded if key[KEY_F2], then when I press F2, the 
compiler stops at the breakpoint, but if I release F2 before I resume, 
then the F2 key appears to be stuck. Only pressing F2 again can unstick 
it. Even pressing other keys does not unstick it.

This problem only appears on Windows 2000. If I do the same under 
Windows 98, the key manages to unstick itself even though it was 
released while the main program was stopping at a breakpoint. I am using 
MSVC 6 and Allegro 4.2.0 final.


AE.

/***************************************************************************
 *
 * breakpointkbdtest.c
 * Test program to show the Allegro keyboard handler failing to release a key if it was released during a break by the debugger.
 *
 **************************************************************************/


/****************************************************************************
 Includes
 */

#include <allegro.h>


/****************************************************************************
  Types
 */

typedef int TeBool;


/****************************************************************************
 Defines
 */





void
teDoTest()
{
	set_gfx_mode(GFX_AUTODETECT_WINDOWED, 640, 480, 0, 0);		
	set_palette(desktop_palette);

	textout_ex(screen, font, "Hold down F2 to display some text", 0, 0, 1, 0);



	while(!key[KEY_ESC] && !key[KEY_SPACE])
	{
		if(key[KEY_F2])
		{
			// Place a breakpoint on the line below to see F2 getting stuck on Windows 2000
			textout_ex(screen, font, "F2 is pressed", 30, 20, 0, 1);
		}
		else
		{
			rectfill(screen,30,20,30+(13*8),20+8,0);
		}


	}

}



TeBool
teSetup()
{
	if(allegro_init())
	{
		TRACE("Error Initialising Allegro.\n");
		return FALSE;
	}


	if(install_keyboard())
	{
		TRACE("Error Initialising Keyboard.\n");
		return FALSE;
	}
	

	return TRUE;
}



void
teCleanUp()
{
	remove_keyboard();

	allegro_exit();
}



int main(void)
{
	if(!teSetup())
	{
		teCleanUp();
		return -1;
	}


	teDoTest();


	teCleanUp();

	return 0;
}
END_OF_MAIN();