Re: [Sexpr-users] parse_sexp crashes

[Matthew S. <mjs...@me...>]

Hi-

I'd be happy to help track down the source of this error that you are  
seeing.  I passed the same string to a simple program myself and it  
worked just fine as you saw.  I am assuming the crash you are seeing  
is a side effect of how the parser is interacting with the rest of the  
program that you are writing.  Do you have a simple program that can  
reproduce the circumstances where a segmentation fault occurs?

Are you using the standard build of the library (ie: you just ran  
"make" with no special target), or are you using the special versions  
(like "make limitmem")?

Any details you can provide would be helpful so I can try to reproduce  
the bug and either debug the library or give you pointers on properly  
using the code.  I'm always happy to give users a hand if they find my  
little library useful! :-)

-matt

On Aug 13, 2009, at 1:34 PM, Hoover,	Ryan L CTR USAF AFMC AFRL/RDSM  
wrote:

> I’m new to sfsexp and mailing lists in general so please go easy on  
> me ;)
>
> SFSexp works great most of the time for me, but there are occasions  
> where parse_sexp() seg faults.
>
> I have confirmed from my Qt version of GDB that this is exactly what  
> I’m passing to parse_sexp:
>
> 0x8b287b8 "(DataKeyValue (oss (xenon-lamp (state OFF) (level 0)  
> (color GRAY) (error NO-ERROR)) (laser-diode (state OFF) (level 0)  
> (color GRAY) (error NO-ERROR)) (resolution-target (state OFF) (pos  
> 0) (color GREEN) (error NO-ERROR)) (target-aperture (state RESET)  
> (pos 0) (color GRAY) (error NO-ERROR)) (phase-plate (state RESET)  
> (pos 0) (color GRAY) (error NO-ERROR)) (injection-mirror (state  
> RESET) (pos -10) (color GREEN) (error NO-ERROR)) (background (state  
> RESET) (pos 0) (color GRAY) (error NO-ERROR)) (target-brightness1  
> (state RESET) (pos 0) (color GRAY) (error NO-ERROR)) (target- 
> brightness2 (state RESET) (pos 0) (color GRAY) (error NO-ERROR)) ))"
>
> (Note the 0x8b287b8 and quotation marks are artifacts of the  
> debugger and not part of the string).
>
> When I look up the backtrace stack I see some malloc’s, so I tried  
> allocating the char array a couple similar (but identical) ways, but  
> to no success. Also, I wrote a simple program that just calls  
> parse_sexp() on this string and it does NOT crash. I’m very confused  
> on this one.
>
> Thanks for your help!
>
>
> Matt Canonicus
> Hawaii
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