[fpc-pascal] crash in tobject.free

[Matthias Klumpp]

Hi!
On Thu, 9 Dec 2010 11:42:20 -0800, David Emerson <dle3ab at angelbase.com>
wrote:
> I'm encountering a consistent crash, and I'm not sure how to address the

> problem.
> 
> using:
> - laz 0.9.28.2-8 beta, svn 22277, from debian testing -- a rather
outdated
> one, 
> because at this point upgrading lazarus requires updating debian
> - fpc 2.4.0-2 [2010/02/20] for i386
> - fpgui commit e01c52a650bfdcce0bb1c8bbceefeb4e8dd46764
> 
> The lazarus popup error message says:
> 
> Project Swindow raised exception class 'External: SIGSEGV'.
> 
> The top of the lazarus call stack shows:
> 
> #0 :00000000 ?? at :0
> #1 :08058BC2 SYSTEM_TOBJECT_$__FREE at :0
> 
> #2 is my own call: if assigned (f_image) then f_image.free;
> 
> I broke up the line, and it's crashing on the "then f_image.free" part,
> rather 
> than on the "if assigned(f_image)" part.
> 
> Any ideas?
Have you initialized f_image? If not, do f_image := nil; and the error
will be gone. (Assigned need this to check if the object exists)
You could also use if assigned (f_image) then FreeAndNil(f_image);
Hope this works!
  Matthias Klumpp