RE: RPG/400 pgm strange behavior

["Richard Jackson" <richardjackson@xxxxxxxxxxxxxxxxxx>]

I refer to an object descriptor whose content can be queried at execution
time.  It is used to verify the properties of parameters passed between
modules when a dynamic call is used.  It requires CPU cycles to use.

This concept is similar to the static checking performed by the link-editor
or module binder but performed dynamically at each call, not statically at
compile time.

Richard Jackson
mailto:richardjackson@richardjackson.net
www.richardjacksonltd.com
Voice: 1 (303) 808-8058
Fax:   1 (303) 663-4325

-----Original Message-----
From: owner-rpg400-l@midrange.com [mailto:owner-rpg400-l@midrange.com]On
Behalf Of James David Rich
Sent: Friday, July 14, 2000 3:39 PM
To: RPG400-L@midrange.com
Subject: RE: RPG/400 pgm strange behavior


On Thu, 13 Jul 2000, Richard Jackson wrote:

> I think that ILE includes the concept of a self-describing parameter.
That
> is a parameter that contains its length, type, and attributes in a place
> where all languages can find them.  Loading these independent descriptors
> takes machine cycles that many of us aren't willing to pay.  So, if I call
> your program with the right number of parameters but without the
> descriptors, your program doesn't know what it is getting.  I don't want
> that to change because I want high-performance calls.

Huh???  Parameter checking is done at *compile* time.  The descriptors are
built into the data type (int a, char *string, zoned decimal 5,1).  When
something is compiled and linked into an executable parameters are
checked.  The linking stage removes references to outside objects and
binds stuff together into one object.  So a call doesn't need to check
parameters anymore.  A call just becomes an instruction to run from
another spot in the stack.  No loading, no checking, no cycles.  Of course
this is only with ILE and only when calling bound modules - something
like:

C               eval    err = my_function(parm1:parm2)

James Rich
james@dansfoods.com

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