suppressing error messages



Ugh. Some of us routinely name files jnk.txt. Surely there is a better 
way. 
I think when I asked about this before the answer was something like:

(%i1) f(a,b) := block([errormsg : false], a : errcatch(a/b), if a = [] 
then 'und else first(a))$

But this doesn't work:

(%i2) f(0,0);
Division by 0
(%o2) und

(%i3) f(0,0);

(%o3) und

Barton

maxima-bounces at math.utexas.edu wrote on 07/09/2009 02:13:26 PM:

> [image removed] 
> 
> Re: [Maxima] suppressing error messages
> 
> Richard Hennessy 
> 
> to:
> 
> Barton Willis, Maxima Mailing List
> 
> 07/09/2009 02:13 PM
> 
> Sent by:
> 
> maxima-bounces at math.utexas.edu
> 
> f(a,b) := with_stdout("c:/jnk.txt", a : errcatch(a/b), if a = [] 
> then 'und else first(a));
> 
> 
> ----- Original Message ----- 
> From: "Barton Willis" <willisb at unk.edu>
> To: "Maxima Mailing List" <maxima at math.utexas.edu>
> Sent: Thursday, July 09, 2009 12:25 PM
> Subject: suppressing error messages
> 
> 
> How can I suppress the error message (Division by zero in this case) in 
a
> function
> such as: (the function f is just a toy---I wasn't wanting to do anything
> like this)
> 
> (%i7) f(a,b) := (a : errcatch(a/b), if a = [] then 'und else first(a));
> (%o7) f(a,b):=(a:errcatch(a/b),if a=[] then 'und else first(a))
> (%i8) f(0,0);
> Division by 0
> (%o8) und
> 
> I think I've asked about this before, but I can't find it or remember 
the
> trick.
> 
> 
> Barton
> 
> 
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