Re: Fatal crashes on Windows

[Matthew Flatt <mflatt@cs.utah.edu>]

Quoting Peter Lane:
> I've been putting together a data analysis tool in the PLT Scheme 
> v.103p1 environment.  At present, I seem to have encountered a 
> problem with the GUI environment, which is leading to fatal crashes 
> on windows systems, specifically Windows98 and WindowsME.  Sometimes 
> my program just crashes, sometimes it continues but widgets are 
> painted white, and sometimes the following message appears:
> 
> >program Error fatal class WxWindows
> >Error: Can't create window of class WxCanvasClass (87).

This might be due to a bug that's already fixed in v200, related to
event handling and update events. Although 200alpha1 has some problems
in Windows, it's probably worth spending a little time to upgrade,
especially since an improved 200 will be available soon:

   download.plt-scheme.org

But since you mention Windows 98 and Me specifically, I wonder whether
it has anything to do with pens and brushes. If you allocate many pens
and brushes with `(make-object pen% ...)' and `(make-object brush%
...)' then Windows might be running out of graphics memory. If you
don't mutate the pens and brushes, then using `(send the-pen-list
find-or-create-pen ...)' and `(send the-brush-list find-or-create-brush
...)' will likely help. (Windows NT, 2000, and XP wouldn't have this
problem, because they don't distinguish GUI memory from normal memory.)

Matthew