RE: Using *OMIT & *NOPASS

Here is one possibility, but I don't know whether it would work as I haven't
tried it:

In program X set-up two based variables: b2,c2 (based on bptr, cptr)
Then load the basing pointers with the address of the actual parameter if it
has been passed.
Thus you pass along a null pointer if it has not been passed.

You still have to use %parms, but only once in the program.

Here's the code (I've marked the lines I've changed:

Proc X (a, b *nopass, c *nopass)
D B2      S         BASED(BPTR) <
D C2      S         BASED(CPTR) <
C         IF   %Parms>=2                <
C         Eval BPTR = %ADDR(B)  <
C         ENDIF                         <
C         IF   %Parms>=3                <
C         Eval CPTR = %ADDR(C)  <
C         ENDIF                         <
if control file say one thing
        return Y (a,b2,c2)              <
else
        return W (a,b2,c2)              <
endif
end proc X


Program Z
callp x(a,b)
end pgm z


Proc Y (a, b *nopass, c *nopass)
do stuff
end proc Y

Proc W (a, b *nopass, c *nopass)
do other stuff
end proc Y

-----Original Message-----
From: David Gibbs [mailto:dgibbs@mks.com]
Sent: 28 November 2001 15:57
To: 'RPG400 Mailing List'
Subject: Using *OMIT & *NOPASS


Folks:

I've got a bit of a quandary... We've been writing a number procedures that
have a variable number of parameters.

These procedures, in turn, call other procedures that also have a variable
number of parameters.  The two procedures have very similar (if not
identical) parameter lists ... but the called parameter might call a
different procedure based on a control file.

I made the erroneous conclusion that if a parameter was not passed, it's
address would be set to *NULL (similar to passing *OMIT).

So, the question is ... what is the best way to handle possibility unpassed
parameters without having to code a complex structure of "if %parms > 2,
call w/ 3 params, if %parms > 3, call w/ 4 params", etc?

Here's a quick pseudocode of what we are doing...

Program Z

callp x(a,b)

end pgm z

Proc X (a, b *nopass, c *nopass)

if control file say one thing
        return Y (a,b,c)
else
        return W (a,b,c)
endif

end proc X

Proc Y (a, b *nopass, c *nopass)

do stuff

end proc Y

Proc W (a, b *nopass, c *nopass)

do other stuff

end proc Y


david

--
David Gibbs
Sr. Software Engineer
MKS, Inc.
2500 S. Highland Ave, Suite 200
Lombard, IL  60148
(630) 495-2108 x5004

Need a laugh (we all do these days): visit http://www.userfriendly.org

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