1. I would not agree that the following items relate specifically to ILE.
ILE - Integrated Language Environment - refers to the environment in which
an RPG program module is compiled and executes.
It allows for multi-language programs, improved memory management and
inter-program communication. ILE is not language specific.
The following notes specifically refer to RPG, but may be relevant to other
languages such as ILE COBOL and ILE C.
2. The procedure and the subroutine are called and executed away from the
calling code. For exampoe, an invoicing program and a credit note program
can both use the same sales tax procedure or subroutine. A procedure is a
recent innovation - subroutines came in a very early release of RPG.
2a The sales tax procedure can exist as a compiled module and linked into
the executable program as the final compilation step. It can have values
passed into it as parameters, and can return a value as a return parameter.
The input values may be changed from within the procedure - thus they
may in fact be input / output parameters.
A constant may be passed as an input parameter.
Parameters may be passed as values or as pointers.
All variables defined in a procedure, apart from parameters, as local
to the procedure.
Local variables retain their values from call to call within each run
of th program.
Variables which are input / output to the program are global.
Subroutines may be defined within a procedure.
Such subroutines are local to the procedure.
A procedure can be an external procedure, in that it is compiled
separately and linked in as the final compile step.
An internal procedure is coded inline with the program, or included
with a copy statement.
2b A subroutine is typically defined at the end of the calcs.
It does not take nor return parameters.
All subroutine variables are global.
3 The purpose of protoyyping is to proviude a single definition for the
calling of a procedure. It lists the parameters - if any - of the procedure
and some related information.
In practical terms, the prototype ensures consistency across the
prototype and the associated calls.
Each program which calls thye procedure must contain the prototype
statement(s), either inline or by use of a copy statement.
4 EXPORT and IMPORT, to put it simply, are used to copy data definitions
between procedures.
5a A procedure may be called by a bound call.
5b A procedure may be coded inline, or it may be copied by a copy
statement, or it may exist as a separately compiled object and linked in as
the final compile step.
I hope this helps.
John McKay mba
www.rpglanguage.com
www.mckaysoftware.ie
----- Original Message -----
From: "Adam West" <adamster@xxxxxxxxx>
To: <rpg400-l@xxxxxxxxxxxx>
Sent: Wednesday, January 07, 2009 2:45 AM
Subject: Some ILE questions.
HI In ILE, I have had trouble understanding some of these concepts.
the Procedure, is the same as a subroutine? except for the fact that you
can pass parameters and have different data types?
What is the purpose of prototyping Procedures?
What does the Export and Import do?
Typically the Procedure is bound or is it brought in via a /Copy
directive?
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