Re: Using *OMIT & *NOPASS

["Simon Coulter" <shc@xxxxxxxxxxxxxxxxx>]

"
Hello David,

There is no truly elegant way to handle this.  However you could have proc x
set appropriate defaults and always call Y and W with the full complement of
parameters.  For example

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

set my_B to default
set my_C to default

if (%parms >= 2)
        set my_B to b

if (%parms >= 3)
        set my_C to c

if control file say one thing
        return Y (a,my_B,my_C)
else
        return W (a,my_B,my_C)
endif

end proc X

You could also specify *OMIT rather than *NOPASS on the prototype thus
forcing your caller to pass *OMIT as a placeholder.  Since *OMIT does pass
something (a null pointer indicating nothing) you could simply pass that on
to Y and W.  This will certainly work when the called proc checks for parms
using the form: if (%addr(parm) <> *NULL)       but may not work if using
the CEE API to check for omitted parameters.  I haven't tried it so I don't
know for certain.  NOTE: forcing *OMIT is pretty ugly and will likely
irritate the caller.

You could also allow both *OMIT and *NOPASS  but that requires that you
first check %PARMS to determine if something was passed and then use the CEE
API to check for omitted parameters.  You cannot use the %addr(parm) method
because the compiler will not allow you take the address of a *NOPASS
parameter.

None of these techniques result in elegant code in the procedure that
implements the function but they do allow an elegance in the procedure
interface which may simplify your caller's code.

Regards,
Simon Coulter.

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