Path: utzoo!utgpu!jarvis.csri.toronto.edu!rutgers!usc!cs.utexas.edu!uunet!ingr!b11!doyle
From: doyle@b11.ingr.com (Doyle Davidson)
Newsgroups: comp.windows.x
Subject: Re: SIGFPE in miFillSppPoly()
Message-ID: <5331@b11.ingr.com>
Date: 23 Jun 89 15:15:39 GMT
References: <8906211551.AA07986@inria.inria.fr>
Organization: Intergraph Corp. Huntsville, AL
Lines: 35

In article <8906211551.AA07986@inria.inria.fr>, rob@cetia.UUCP writes:
> Occasionally we get Not-a-Number floating point exceptions in ceil()
> called from miFillSppPoly().
...
> i have looked at the code, briefly, for miFillSppPoly()
> and it does seem possible that the variables xl and xr could be passed
> to ceil() without having been initialized.
> The algorithm might actually preclude this but i haven't examined it that
> closely.
> 
From looking at the code myself (which am and trying not to use since
we are having problems with truly meeting the X spec and I think this
is the culprit)  The only way that I can see xl and xr not being initialized
is if the points passed in (which have to be 3 or more) are all linear
(and may actually have to be horizontal too i.e. dy=0)
which seems rather difficult since it is called from:
    miWideLine - a line always has width so won't be linear points
	(0 width will be treated as width 1 if it makes it here)
    miarc.c    - can't say for sure about this one
    miWideDash - can see any way here since dashes once again have width
    (did I miss any folks?)

So my real question is what are you doing that is causing this weird value?

Doyle (mi code is slow, and it doesn't work too) Davidson
------------------------------------------------------------------
Doyle C. Davidson              |
Intergraph Corp.               |  These comments are...
Workstation Graphics Standards |
1 Madison Industrial Park      |     \\  /
Huntsville, AL 35806           |      \\/
(205) 772-2000                 |      /\\  clusively my own.
                               |     /  \\
..!uunet!ingr!b11!doyled!doyle |
------------------------------------------------------------------