From:	mert0407 AT sable DOT ox DOT ac DOT uk (George Foot)
Newsgroups:	comp.os.msdos.djgpp
Subject:	Re: Post mortem debugging and the like...Help...
Date:	13 Nov 1996 15:55:13 GMT
Organization:	Oxford University, England
Lines:	41
Message-ID:	<56cr11$sro@news.ox.ac.uk>
References:	<3289C871 DOT 58DE AT magna DOT com DOT au>
NNTP-Posting-Host:	sable.ox.ac.uk
To:	djgpp AT delorie DOT com
DJ-Gateway:	from newsgroup comp.os.msdos.djgpp

Martin..... (beable AT magna DOT com DOT au) wrote:
: G'day,

: like what the old modula-2 compilers used to have, where if an
: unexpected crash occured, the compiled program would write out a dump
: file which could later be analized with a debug version of the code.

If your program crashes and produces an error report listing all CPU 
registers, etc. and the stack trace, type SYMIFY <exe_name> while this is 
still on the screen. Provided you left the debugging information in, this 
will write function names after the stack trace addresses. This shows you 
which function was being called when the error occured, and which called 
it, etc. If this information is lost for some reason, redirect stderr to 
a file using REDIR, then attempt to reproduce the error, and run SYMIFY 
using the text file produced.

: 	Of what value is the 'eip=' number and is this a pointer or clue as to
: what could have gone wrong in the program?? Is there any other method of
: debugging a DJGPP executable after the fact??

At a guess, it shows the instruction which was being executed when the 
problem occured. I'm not sure how one would go about tracing this back to 
the source code; presumably some of the debuggers can do this.

If you intend your users to submit bug reports, it's probably best to ask 
them to send you the stack trace, and EIP if you can trace it back. You 
can't really supply them with symify and expect them to use it sensibly. 
Also, you probably want to strip the debugging information before you 
release the program.

--
George Foot

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