Re: Procedure PR/PI question

Wow, that is the first time I ever heard (or read) someone describe the
use of pointers in C as 'simple, elegant and predictable'! The fact that C
only passes parameters by value leads to extensive use of pointers, which
first brought us the widespread disease of memory loss and later, as a
remedy, Java :-)

Joep Beckeringh

whatt sson

Joep, thats what i meant.

Some other
The keywords "value" and "const" are a bit confusing. In C (RPG these

days

seems to be a bit of a strange mix of C and Pascal syntax and semantics)
all parameters are passed simply by value. The keyword "const" means

that

you can not change it within the called function (of course you can

still

change it through other references). If you have complex data (not just
simple datatypes) you can pass a pointer (which is passed by value like

all

other datatypes). In C it's more common to work with pointers. This is
simple, elegant and predictable. You have only one way of passing
parameter, namely "by value". If you don't want to copy lots of data on

the

stack you simply use &var (%addr(var) in RPG).

So i think i'm going to use "value" always (not with local procs only).

And

if i need to pass lots of data (in principle always if i want to pass

more

than just a basic type) i pass a pointer. The latter can be done with

%addr

in the caller or by definining the parameter as "const". However if i

use

"const" the behavior is not consistent. The compiler decides whether to
copy the variable or not (and i never want a copy just the const). This

way

the semantics are the same as in C (except for the use of const), which
comes in handy if i ever want to convert the code to C. I don't see a

real

downside in this approach, except that it makes more use of pointers

with

which many RPG'ers are not comfortable. And that the semantics of

"const"

is not the same as in C. So i'm still in doubt whether to use const (if

i

want to pass a pointer) or use "value" with %addr. The latter case is a

bit

convoluted but we're used to that in RPG (need at least 6 specs to start

a

free form procedure impl without even one parameter). But i can't use

the

const semantics of keyword "const" (like in C) because it mostly also

means

"copy".