Re: Procedure calls

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

Hello Nelson,

You wrote:
>If I have duplicate procedure names, both in my local modules and/or in
>service programs that are in my binding directory, and use *DUPPROC on my
>compile commands, what method does the compiler use to determine which
>version of a proc it uses?  The order that they are listed on the binding
>directory?  Do local procedures take precedent over a service program
>procedure of the same name?  Is there anyway to qualify a procedure call?
>Is it a set method that can be counted on to repeat each time, or is it
>unpredictable?  The ILE Concepts manual seems pretty vague on this.

Perhaps, but the help text is not so vague:
"
*DUPPROC
    During the symbol resolution phase of the binding
    process, the procedure names that are exported from
    the modules and service programs do not have to be
    unique.  When multiple duplicate procedures are
    allowed, the first exported procedure in the list of
    specified modules and service programs that matches
    the import request is the procedure that is selected.
"

The binder simply takes the first reference found.  That means it looks at
the list of modules on the MODULE keyword, then it looks at the service
programs listed on the BNDSRVPGM keyword, then it uses the contents of the
binding directories, in order, listed on the BNDDIR keyword.  It doesn't
care if a procedure is bound by copy or bound by reference.  For example,
if you have a procedure called doStuff in module X and also in service
program Y then Y.doStuff will be used if Y is listed in the binding
directory before X.

Simple but crap!  Until support is provided for qualified or overloaded
procedure calls you should not be using duplicate exported procedure names
nor duplicate variable exports if you can avoid it.

One way to achieve the effect of overloaded or qualified procedure calls
is to get a list of the exported procedures in the service programs
(QBNLSPGM format SPGL0600), activate service programs yourself
(QleActBndPgm), get pointers to the exported proceures (QleGetExp), and
call the procedures via the function pointer.

Regards,
Simon Coulter.

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