Re: Memory Leaks in RPG (was: Is RPG 'DEAD")

["Rory Hewitt" <roryhewitt@xxxxxxxxx>]

David,

Yes, that would work.

When the first job ends, any attempt to access memoryP by job2 would
probably cause an MCH error.

The user space *doesn't* know that it's a pointer - as you pointed out, it's
up to the programs that reference that data to specify that it's a pointer.
However, the difference between a user space and a data area/data queue etc.
is that you *can* *technically* store a pointer inside a user space, because
the user space can also store the tags etc.

Rory

On Thu, Jun 19, 2008 at 11:29 AM, David Gibbs <david@xxxxxxxxxxxx> wrote:

> Bruce Vining wrote:
> > A *USRSPC can store a pointer, but a *DTAARA, *DTAQ, or database file
> > cannot.  The pointer will not be considered to be valid when you try
> > to use it later.
>
> Ok, I'm certainly learning stuff today.
>
> So, given the following program in one job ...
>
> ----------
> Dsomefield        S             10A   inz('ABCDEFG')
> DmemoryP          S               *   based(userSpaceP)
> DuserSpaceP       S               *
>
>  /free
>   ibmQUSPTRUS(qualifiedUsName:userSpaceP);
>
>   memoryP = %addr(somefield);
>
>   // do other stuff
>  /end-free
> ----------
>
> ... and a this program in another job ...
>
> ----------
> Dsomefield        S             10A   based(memoryP)
> DmemoryP          S               *   based(userSpaceP)
> DuserSpaceP       S               *
>
>  /free
>   ibmQUSPTRUS(qualifiedUsName:userSpaceP);
>
>   if somefield = 'ABCDEFG';
>     // do something to indicate the memory is the same
>   endif;
>
>  /end-free
> ----------
>
> Would work???
>
> What happens if the first job ends?
>
> How does the user space know that the information stored in it is a
> pointer?
>
> Thanks!
>
> david