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February 2009

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2009.02.05 18:38 "assertions, and building with DEBUG/NDEBUG", by Frank Warmerdam
2009.02.05 19:04 "Re: assertions, and building with DEBUG/NDEBUG", by Edward Lam
2009.02.05 19:13 "Re: assertions, and building with DEBUG/NDEBUG", by Bob Friesenhahn
2009.02.05 19:26 "Re: assertions, and building with DEBUG/NDEBUG", by Frank Warmerdam
2009.02.05 20:00 "Re: assertions, and building with DEBUG/NDEBUG", by Bob Friesenhahn
2009.02.06 04:39 "Re: assertions, and building with DEBUG/NDEBUG", by Phillip Crews
2009.02.06 16:33 "Re: assertions, and building with DEBUG/NDEBUG", by Bob Friesenhahn
2009.02.06 20:34 "Re: assertions, and building with DEBUG/NDEBUG", by Phillip Crews
2009.02.06 12:17 "Re: assertions, and building with DEBUG/NDEBUG", by <ron@debian.org>
2009.02.06 13:57 "Re: assertions, and building with DEBUG/NDEBUG", by Edward Lam
2009.02.06 17:08 "Re: assertions, and building with DEBUG/NDEBUG", by Bob Friesenhahn
2009.02.06 21:05 "Re: assertions, and building with DEBUG/NDEBUG", by Phillip Crews
2009.02.06 10:07 "Re: assertions, and building with DEBUG/NDEBUG", by Joris Van Damme
2009.02.06 15:05 "Re: assertions, and building with DEBUG/NDEBUG", by Frank Warmerdam
2009.02.06 10:44 "Re: assertions, and building with DEBUG/NDEBUG", by Joris Van Damme
2009.02.06 14:56 "Re: assertions, and building with DEBUG/NDEBUG", by Frank Warmerdam
2009.02.07 10:53 "Re: assertions, and building with DEBUG/NDEBUG", by Joris Van Damme
2009.02.07 14:10 "Re: The OJPEG bug 1996", by Joris Van Damme
2009.02.26 22:44 "Re: assertions, and building with DEBUG/NDEBUG", by Joris Van Damme

2009.02.06 16:33 "Re: assertions, and building with DEBUG/NDEBUG", by Bob Friesenhahn

On Thu, 5 Feb 2009, Phillip Crews wrote:
>
> In a library like libtiff, it is inappropriate to abort the calling
> program when an assertion is triggered, which a failed assert() does on
> many platforms.
>
> In my code, I use my own macro, which is defined as assert() in debug
> builds, but in release builds calls an internal logging routine and
> continues. If a severe problem or crash occurs later because of the bad
> value, I have information to go on in the log.

It is quite often (most often) not appropriate to proceed with 
processing once an assert has been encountered.  Doing to risks heap 
corruption, and potential exploits from intentionally malligned files. 
If any heap or stack corruption has occured, then the process is then 
in an instable state.

The key thing is to discriminate between issues which are best 
reported as errors, warnings, or assertions.  Assertions should always 
stop processing since they should be used to detect logic (i.e. 
design/implementation) errors.  Warnings result in a message to the 
user, but processing continues.  Errors result in a message to the 
user, and a return to the invoking code with no further processing of 
the current file.

Bob
======================================
Bob Friesenhahn
bfriesen@simple.dallas.tx.us, http://www.simplesystems.org/users/bfriesen/
GraphicsMagick Maintainer,    http://www.GraphicsMagick.org/