Re: XForms: Function causes segmentation fault

Christopher Harrop (harrop@radon.cs.uoregon.edu)
Sat, 7 Jun 1997 11:45:52 -0700 (PDT)

To subscribers of the xforms list from Christopher Harrop <harrop@radon.cs.uoregon.edu> :

I have been experiencing strange crashes when using the v0.86, 64-bit SGI
library (for R10K) on IRIX 6.2. I reported the problem some time ago,
but did not really understand it, so eventually gave up. I have been
using the 32-bit library without difficulty. I believe I now have some
more clues.

I have isolated the problem (described below) I am having to the use of
input fields. The FL_HIDDEN_INPUT input field appears to be the only one
that works correctly.

The problem:

If there is an input field anywhere on a form, the form will
become trashed when the form is dragged too quickly across
the screen, or when the form is partially hidden and then
subsequently brought to the foreground. The application then
crashes.

The exact error reported from XForms:

In FLColor [flcolor.c 648] Bad request 34359738368
In FLColor [flcolor.c 648] Bad request 901943132164
X Error of failed request: BadDrawable (invalid Pixmap or Window
parameter)
Major opcode of failed request: 74 (X_PolyText8)
Resource id in failed request: 0x600004e
Serial number of failed request: 645
Current serial number in output stream: 647

Tests:

1) My form behaves correctly without the input field.
2) Adding the input field causes it to crash as described above.
3) The inputall demo suffers from the same problem as my code, with
EXACTLY the same symptoms. This is evidence that my code is not to
blame.
4) FL_HIDDEN_INPUT appears to function correctly. All other input field
types appear to be buggy.
5) No problems with 32-bit or n32-bit.

Questions:

I did not see anyone else report this problem.

1) Is this new?
2) Can anyone else reproduce this?
3) Do others have trouble with the inputall demo for v0.86 64-bit on
SGI IRIX6.2? (drag it VERY quickly across the screen, or cover it
and then uncover it; it should crash).
4) Is there a known fix or workaround?

Chris
-----------------------------------------------------------
Chris Harrop University of Oregon
PhD Student Computer Science Dept
harrop@cs.uoregon.edu Eugene, OR 97403
http://www.cs.uoregon.edu/~harrop/ 541-346-0892

"If you don't have time to do it right, you sure as hell
don't have time to do it over!" -- Richard Winkler

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