Re: Pointers and LR

[Ken Sims <mdrg5003@xxxxxxxxxxx>]

Hi Albert -

> I have a program which returns a pointer to a string. It currently setons 
> on LR before returning. I use the pointer in subsequent programs and 
> everything seems to work okay. However, will that memory location 
> eventually be re-used, since I set on LR?

If the caller owns the storage you're okay.

If the called program owns the storage directly (i.e. by a definition in 
the program rather than allocated storage as described below), this 
situation is an accident looking for a place to happen.

I would try to have the caller own the storage.  If that's not possible, 
have the called program return with LR off.  When the caller is done with 
the storage, call the program with no parameters.  Have the called program 
set on LR and return if the number of parameters passed is zero.

Another option is for the called program to ALLOC the storage and make sure 
that the ALLOC pointer is passed back.  The caller can deallocate the 
storage later.  Both programs must reside in the same activation group.

Ken
http://www.kensims.net/
Opinions expressed are my own and do not necessarily represent the views
of my employer or anyone in their right mind.