Re: CONST and VALUE revisited

[Vern Hamberg <vhamberg@xxxxxxxxxxx>]

David

In our own applications there is almost no reason to use VALUE that I 
can think of. The main reason is to call certain APIs that have 
parameters defined as integers, and these are by value. These tend to be 
C/C++ APIs. Things like the access() function that acts like a CHKOBJ - 
it uses an integers for some of its parameters, as I recall, and you get 
spurious results if you don't use *BYVAL in a CL or VALUE in RPG.

Even when using CONST on a large parameter, only 16 bytes are passed - 
for the pointer - even though a copy might be made of the original 
variable. At least the entire variable is not being passed.

HTH
Vern

David FOXWELL wrote:
> YES! That was it! That's the problem I have had come across from time to time.
> Now in my old RPG3 that I'm converting, I was hoping that I'd get away with not doing unnecessary analysis by simply using VALUE.
>
> I admit it, in this case VALUE instead of CONST is a quick fix. Normally, the program would be written in RPGLE and we'd use CONST and that'd be it.
>
> So, in a 100% RPG application, what kind of situation merits the use of VALUE?
>
>
> -----Message d'origine-----
> De : rpg400-l-bounces@xxxxxxxxxxxx [mailto:rpg400-l-bounces@xxxxxxxxxxxx] De la part de Barbara Morris
> Envoyé : jeudi 29 janvier 2009 02:43
> À : rpg400-l@xxxxxxxxxxxx
> Objet : Re: CONST and VALUE revisited
>
>
> There's one way a CONST parameter can be changed while the procedure is running.  If you pass a global variable by CONST to a subprocedure in the same module, and the subprocedure modifies the global variable directly, then the value of the CONST parameter may reflect the change.
>   It would depend on whether the compiler had passed the global vairable directly or whether it had used a temporary.
>
>