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Re: Detecting and handling error messages?

• To: mathgroup at smc.vnet.net
• Subject: [mg24236] Re: Detecting and handling error messages?
• From: Jens-Peer Kuska <kuska at informatik.uni-leipzig.de>
• Date: Tue, 4 Jul 2000 15:22:02 -0400 (EDT)
• Organization: Universitaet Leipzig
• References: <8jrbto$dqe@smc.vnet.net>
• Sender: owner-wri-mathgroup at wolfram.com

Hi,

the manual say:

"Check[expr, failexpr] evaluates expr, and returns the result, unless \
messages were generated, in which case it evaluates and returns
failexpr. \
Check[expr, failexpr, s1::t1, s2::t2, ... ] checks only for the
specified \
messages."

BTW: Messages are not only errors/warnings. It is a good way to have
some information printout how an algorithm continues. Then you
don't like to see the messages like "Step 1 done .." you can turn them
off.

Regards
  Jens

AES wrote:
> 
> What I'm really after is a simple way of detecting (testing) if errors
> have occurred during the execution of a given Input cell, so I can note
> this and maybe do something, but without actually having the error
> messages be printed to the screen.
> 
> I note that The Mathematica Book on p. 1155 says
> 
>    Off[symbol::tag] switches off a message, SO THAT IT IS NO
>    LONGER PRINTED   (emphasis mine)
> 
> Page 460 says
> 
>    $MessageList    a list of the messages PRODUCED during
>    a particular computation
> 
> Note:  "produced", not "printed" -- ??
> 
> Page 1249 says
> 
>    $MessageList is a global variable that gives a list of the
>    names of messages GENERATED during the evaluation of
>    the current input line
> 
> "Generated" ?=? "produced" ?=? "printed".
>