Path: utzoo!utgpu!jarvis.csri.toronto.edu!cs.utexas.edu!yale!cs.yale.edu!Duchier-Denys@cs.yale.edu
From: Duchier-Denys@cs.yale.edu (Denys Duchier)
Newsgroups: gnu.emacs.bug
Subject: bug in DoDsp
Message-ID: <12788@cs.yale.edu>
Date: 25 Jan 90 02:48:17 GMT
Sender: news@cs.yale.edu
Reply-To: Duchier-Denys@cs.yale.edu (Denys Duchier)
Organization: Computer Science, Yale University, New Haven, CT 06520-2158
Lines: 36

I don't know if I am dreaming, but here is another piece of code that
seems to be in error.

In function DoDsp (xdisp.c):

  if (pos.vpos < 1)
    {
      cursX = max (XFASTINT (w->left), pos.hpos);
      cursY = this_line_vpos;
      goto update;
    }
  else
    goto cancel;

Shouldn't that be:

  if (pos.vpos < 1)
    {
      cursX = XFASTINT (w->left) + ((pos.hpos < 0) ? 0 : pos.hpos);
      cursY = this_line_vpos;
      goto update;
    }
  else
    goto cancel;

Admittedly the code I found the bug in is slightly different (it's
epoch code), but I think the principle applies here too.

I don't think the problem can be reproduced in standard emacs (perhaps
because of some pessimal redisplay strategy), but in epoch I was
having problems convincing the display code to update the cursor when
I was typing \C-e.

Once again, does anyone know...?

--Denys