[Xcircuit-dev] Xcircuit segfaults on startup under Mac OS X.

[Kevin Brock]

> On Jul 21, 2010, at 11:53 AM, Tim Edwards wrote:
>> Chris wrote:
> . . .
>> > Xcircuit segfaults on startup on my system.  I've attached a report which 
>> > includes a trace and much more info.
>> > The software begins to draw a window but it crashes so fast I can't see how 
>> > far it gets.  I see some gold color and
>> > maybe the widgets and it's all gone in a half second.
>> > 
>> > I can help if you need more info.  At one tie I used to know tcl.tk fairly 
>> > well.  I write code on Solaris and Linux
>> > all day long but know less about Mac OS and so far nothing about xcircuit.
>> 
>> > Date/Time:       2010-07-13 21:54:23.807 -0700
>> > OS Version:      Mac OS X 10.6.4 (10F569)
>> > Report Version:  6
>> > 
>> > Thread 0 Crashed:  Dispatch queue: com.apple.main-thread
>> > 0   libX11.6.dylib                    0x000000010c794e03 CmapRecForColormap + 
>> > 110
>> > 1   libX11.6.dylib                    0x000000010c7952cd XcmsCCCOfColormap + 
>> > 42
>> > 2   libX11.6.dylib                    0x000000010c735a5f XAllocNamedColor + 55
>> > 3   xcircuit.so                       0x000000010c681a55 CvtStringToPixel + 
>> > 130
>> > 4   xcircuit.so                       0x000000010c681b2e xc_alloccolor + 61
>> > 5   xcircuit.so                       0x000000010c67e0dc build_app_database + 
>> > 68
>> > 6   xcircuit.so                       0x000000010c67f054 GUI_init + 2056
>> 
>> Extracting the relevant parts of your crash report, it looks like it
>> crashed under Mac OS due to an invalid colormap.  In GUI_init(), the
>> colormap is set before calling build_app_database(), so that should not
>> be the problem.  The colormap is set by the line
>> 
>>         cmap = Tk_Colormap(tkwind);
>> 
>> so my suspicion is that under Mac OS, unlike other systems, Tk does not
>> report a valid colormap initially, although it is supposed to do so.  I'm
>> not really sure what to do about it, since it appears to be an error in
>> the Tk implementation for the Mac (Tk_MapWindow() doesn't actually wait
>> for the window to be mapped?).  However, you could try changing line
>> 9275 of tclxcircuit.c from
>> 
>>         cmap = Tk_Colormap(tkwind);
>> to
>>         cmap = DefaultColormap(dpy, DefaultScreen(dpy));
> 
> I'm seeing the same problem as Chris.  I tried your suggestion, and it crashes immediately on the call to DefaultColormap.
> 
> Tk_Colormap is returning NULL.
> 
> I'm looking for some examples to see if this is a problem in other Tk based apps on OS X, but I'm not a Tk expert...
> 
> Kevin Brock
> 
> 
>> which may work to bypass the Tk structures and ask for the colormap
>> directly from X11.  Let me know if it makes a difference.

>