Re: How to use debugging tools

[John W. Eaton]

On 19-Sep-2005, Colin Ingram wrote:

| debug> dbg_step
| tiffread: line -1, column -1   <=========    what does this mean??????

It means that the line and column number information was not recorded
for the parse tree element that is being evaluated.

| [...]
| octave:2> dbstop("tiffread","100")
| panic: Segmentation fault -- stopping myself...
| attempting to save variables to `octave-core'...
| save to `octave-core' complete
| Segmentation fault

| ***************************************************************
| 
| dbstatus causes segfaults as well
| 
| [...]
| octave:3> dbstatus("tiffread")
| panic: Segmentation fault -- stopping myself...
| attempting to save variables to `octave-core'...
| save to `octave-core' complete
| Segmentation fault

Please try the following patch.  I think it fixes both problems.

Thanks,

jwe


src/ChangeLog:

2005-09-19  John W. Eaton  <address@hidden>

        * pt-bp.cc (tree_breakpoint::visit_index_expression):
        Avoid dereferencing invalid pointer.


Index: src/pt-bp.cc
===================================================================
RCS file: /cvs/octave/src/pt-bp.cc,v
retrieving revision 1.20
diff -u -r1.20 pt-bp.cc
--- src/pt-bp.cc        26 Apr 2005 19:24:34 -0000      1.20
+++ src/pt-bp.cc        20 Sep 2005 01:21:57 -0000
@@ -363,7 +363,8 @@
        {
          tree_argument_list *elt = *p;
 
-         elt->accept (*this);
+         if (elt)
+           elt->accept (*this);
        }
     }
 }



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