Re: bug in CMPPTRT

[pytel@xxxxxxxxxx]

If I understand correctly, CMPPTRT compares pointer type, not pointer
values.
Second operand null means "there is no pointer here".
So result of first CMPPTRT means, that P is a pointer (it was initialized
to bad value - probably NULL pointer, but still a pointer), and result of
second CMPPTRT means that Q is not a pointer (was not initialized - only
memory allocated).

    Alexei Pytel



Gene_Gaunt/ReviewWorks@reviewworks.com@midrange.com on 09/29/2000 02:42:22
PM

Please respond to MI400@midrange.com

Sent by:  owner-mi400@midrange.com


To:   MI400@midrange.com
cc:
Subject:  bug in CMPPTRT



Seems CMPPTRT returns a "not equal" condition when it compares a null value
to an unresolved system pointer containing an invalid initial value.  Why?
Shouldn't this situation return an "equal" condition?  In the following
little program at the breakpoint, FLAG1 has value "0" while FLAG2 has value
"1".   Shouldn't FLAG1 have value "1" too, since pointer P and pointer Q
are both null and both will fail in a CALLX operand 1?

DCL SYSPTR P AUTO INIT("BADNAME!!");
DCL SYSPTR Q AUTO;
DCL DD FLAG1 AUTO CHAR(1);
DCL DD FLAG2 AUTO CHAR(1);

CMPPTRT(I) P, * / EQ(FLAG1);   /* becomes "0" */
CMPPTRT(I) Q, * / EQ(FLAG2);   /* becomes "1" */
BRK "LOOK";


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