CL *PTR compare to *NULL; was Re: Environment Variables in RPGLE

Thanks, I will do that. I had that PTF SI27418 for my programs for some time now; the PTF Tom noted. Actually SI28620 is the latest, a correction to a MONMSG issue someone on this list encountered.
I also saw the code sample that Tom gave a link for in a prior message, and he had used the same DCL &NULL_PTR *PTR concept to then use that variable in a later COND(&MYPTR *EQ &NULL_PTR) as you suggest.
I must admit, I had not expected that to work; i.e. I expected that compare would cause a MCH3601 too. I had almost even coded up a CMPPTRT without ever having testing the compare to an initialized to *NULL pointer.
I do wish CL had declared constants; I dislike using a variable as a constant, even with an obvious name :-) I guess I could lobby for %addr(*NULL) but I think just some documentation that can be found easily would be sufficient -- I had looked for how to compare a CL pointer to a /null pointer/ without any luck. I should have submitted a Reader Comment card when I did not find anything. :-Q

Regards, Chuck