Re: CONST and VALUE revisited

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.