Path: utzoo!attcan!uunet!cs.utexas.edu!usc!snorkelwacker!bloom-beacon!SABER.COM!jimf
From: jimf@SABER.COM
Newsgroups: comp.windows.x
Subject: Re: Debugging Graphics Programs
Message-ID: <9009171419.AA04532@armory>
Date: 17 Sep 90 14:19:43 GMT
Sender: root@athena.mit.edu (Wizard A. Root)
Organization: The Internet
Lines: 37

|I'd like to debug a program I've written in X that simply opens a window
|and draws in it.  However, when I use dbx or gdb, the window does not
|open nor can I see any graphics being drawn as the program executes.  If
|I simply execute the program, it opens its window and draws in it just
|fine.  How can I get the debugger to open the window and draw into it as
|the program executes?

You're seeing the effects of buffering.  Put in code to turn X
debugging mode on, which makes the calls fully synchronous for easy
debugging but which slows performance somewhat:

	main()
	{ Display *disp;

	  /* set up display variable */
	  XSynchronize(disp, 1);
	  /* do your thing... */
	}

This can also be accomplished by setting the _XDebug flag to true:

	extern _XDebug;

	main()
	{
	  _XDebug= True;
	  /* do your thing... */
	}

Alternatively you can call XFlush before a breakpoint.  In Saber-C you
can use the following action point:

	{ XFlush(disp); saber_stop(""); }

jim frost
saber software
jimf@saber.com