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From: rouaix@fitou.uucp (Francois Rouaix)
Newsgroups: comp.sys.amiga.tech
Subject: AREXX technical question
Keywords: interface error
Message-ID: <280@seti.inria.fr>
Date: 12 Oct 89 09:03:21 GMT
Sender: news@seti.inria.fr
Reply-To: rouaix@inria.inria.fr (Francois Rouaix)
Organization: The Software Winery
Lines: 50


Here is a "technical" question about AREXX. I post is here instead of
comp.lang.rexx since it may be Amiga dependent. 
If  you're not familiar with AREXX interfacing,  you might want to skip 
the rest of the article...

When you write an AREXX interface for some application (let say
with minrexx for example), you have the choice between using commands 
and functions. The difference for the user is schematically

For a command host:
address 'myhostportname' 'cmd' par1 par2 ... parn
(eventually with option results if you want a result)

For a function host:
1> rxlib cmdhost
and in scripts
res=cmd(par1,par2,...,parn)

The host may be considered both as a command host, or a function host,
provided it looks at flags RX_COMM / RX_FUNC in the messages, and treats
parameters in the appropriate way (ie all parameters in one string
for commands, and a parameter per string in function calls).

The problem I have is that I can't get error codes when I use
function calls.
When  using commands, it's easy to return the rexx msg with the primary
and secondary error codes, so that the script might look at 
the rc variable to handle the error.
However, when I use functions, rx produces an error
"error in external function" (i don't have the exact reference here)
and I didn't find a way to get some information on what error occurred.
My question is: is it possible, and how should i do this ?

Thanks for your help
--Francois

PS: i'll tell you the reason i have for using functions instead of
commands. suppose  one of your parameters is an amigados file name.
It may contain almost any character, in particular spaces.
In command mode, since all parameters are in the same string, it is not
possible to extract the exact file name without using a quoting mechanism,
which is tedious.....
(Auxiliary question: do we have a character that may *never* appear
in an amigados filename ?)

*- Francois Rouaix                 //       We are all prisoners here,       *
*- rouaix@inria.inria.fr         \X/           of our own device             *
*- SYSOP of Sgt. Flam's Lonely Amigas Club. (33) (1) 39-55-84-59 (Videotex)  *
Disclaimer: Opinions expressed are my own, not those of my employer.