1.5.25: Problem with XtAppAddWorkProc and OptionMenu

Jon TURNEY jon.turney@dronecode.org.uk
Wed Jul 15 21:44:00 GMT 2009

On 10/07/2009 09:19, Wakker, P.H. (Pieter) wrote:
> I am running CYGWIN 1.5.25 on Windows XP pack 2. I have a XWindows
> graphics program that uses several XmOptionMenu widgets. The problem is
> that whenever the user clicks frequently (sometimes a double-click is
> enough) on these OptionMenu's the program crashes with a segmentation
> error. This behaviour is not noticeable with the same program on HP-UX.

I'm not sure what this means you tried? Building the same client program on 
HP-UX (which possibly has a completely different lesstif/motif library)?

I am dubious this is a cygwin-specific issue (Cygwin's lesstif only has a 
couple of minor patches to the configury to make it build)

> I reproduced the problem in the test program below. It seems as if the
> combination of the WorkProc and the OptionMenu causes the problem. If I
> remove the XtAppAddWorkProc statement there is no problem, but the only
> widget that causes the crash is an OptionMenu (for example with a
> PushButton I can't reproduce the crash).
> Another thing I noticed is that when I reduce the number of microseconds
> in the usleep command, I have to click faster to make the program crash.
> It seems as if there is a relationship with how long the program is busy
> in the WorkProc. In the actual program the usleep is replaced by
> something useful of course.

Thanks for the test-case.  With a bit of frantic clicking, I can reproduce the 
problem with a crash in XmInputInGadget().  Unfortunately I have no clue about 
lesstif internals so you might get more help via [1]

[1] http://www.lesstif.org/bugs.html

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