Re: How to use debugging tools

[Colin Ingram]

John W. Eaton wrote:

> On 19-Sep-2005, Colin Ingram wrote:
>
> | I have problems using the debugging tools (dbstop, dbg_next etc)
> | 
> | octave:1> debug_on_warning = 1
> | debug_on_warning = 1
> | octave:2> tiffread("2005.08.24-12-1-4.tiff")
> | warning: in /share/colin/Work/programs/frapfitter/trunk/lib/tiffread.m 
> | near line 137, column 9:
> | warning: tiffread:assignIFDentry: some elements in list of return values 
> | are undefined
> | keyboard: stopped in 
> | /share/colin/Work/programs/frapfitter/trunk/lib/tiffread.m at line 137
> | debug> dbwhere
> | error: dbwhere: must be inside of a user function to use dbwhere
> | debug> dbstop("tiffread.m","142")
> | error: dbstop: unable to find the function requested
> | debug> dbstop("tiffread","142")
> | panic: Segmentation fault -- stopping myself...
> | attempting to save variables to `octave-core'...
> | error: octave_base_value::save_binary(): wrong type argument `file'
> | save to `octave-core' complete
> | Segmentation fault
> | address@hidden:~/frapfitter/trunk/lib$
>
> What version of Octave are you using?  On what kind of system?
>
>  
I use debian

address@hidden:~$ uname -a
Linux Alfalfa 2.6.8-2005.05.31 #1 Tue May 31 18:00:26 CDT 2005 i686 
GNU/Linux

address@hidden:~$ octave -v
GNU Octave, version 2.1.71 (i486-pc-linux-gnu).

> I'm unable to crash my copy of Octave with similar commands on an
> arbitrary function (I don't have tiffread).
>
>  
It seems to have something to do with the file.  I have been unable to 
reproduce it with other functions.  Check this out.

**********************************************************
octave:1> dbstop("tiffread","88")
ans = 88
octave:2> tiffread("2005.08.24-12-1-4.tiff")
tiffread: line 88, column 2
TIF
debug> dbgstep
error: `dbgstep' undefined near line 1 column 1
debug> dbg_step
tiffread: line 88, column 12
message
debug> dbg_step
tiffread: line 89, column 13
TIF.file == -1
debug> dbg_step
tiffread: line 89, column 4
TIF
debug> dbg_step
tiffread: line -1, column -1   <=========    what does this mean??????
-1
debug> dbg_step
tiffread: line 100, column 12
byte_order = char (fread (TIF.file, 2, "uchar"))
debug>
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:1> dbstop("tiffread","88")
ans = 88
octave:2> tiffread("2005.08.24-12-1-4.tiff")
tiffread: line 88, column 2
TIF
debug> dbg_step
tiffread: line 88, column 12
message
debug> dbg_step
tiffread: line 89, column 13
TIF.file == -1
debug> dbg_step
tiffread: line 89, column 4
TIF
debug> dbg_step
tiffread: line -1, column -1
-1
debug> dbg_step
tiffread: line 100, column 12
byte_order = char (fread (TIF.file, 2, "uchar"))
debug> exit
warning: broken pipe -- some output may be lost
octave:3> dbstatus("tiffread")
panic: Segmentation fault -- stopping myself...
attempting to save variables to `octave-core'...
save to `octave-core' complete
Segmentation fault
**************************************************************
I've attached tiffread.m.  I've experienced some more strange behavior 
with the db tools but we will save that for later.

Should I prepare a bug report?

> If you think you have found a bug in Octave (and it seems that you
> have, since you've manage to cause Octave to crash with a segfault),
> please submit a complete bug report to the address@hidden list.  If
> you are not sure what to include in your message so that the problem
> might be fixed, then please read http://www.octave.org/bugs.html
> before sending your report.
>
> Thanks,
>
> jwe
>
>
>
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>  



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