Re: ILE bug or "feature"?

On Tue, 6 Feb 2001, Douglas Handy wrote:

> Mark,
> 
> >  OK, pop quiz:  What are the values (under debug) of P1x through P5x?
> 
> The same pointers will exist on the stack, and since you defined them the same
> in TEST2, you'll "see" the same values as TEST1 did.  Had you defined P1x
> through P5x as different data types/lengths, what you'd "see" would be based 
>on
> the same starting address of the XTEST program variables.  For example, if you
> defined P1x as 5 long, it would "see" it as 'ABCDE' and if you defined P4x as 
>5
> long it would "see" it as 'xyz12'.  If you defined one as a packed decimal
> number, you'd get a decimal data error if you referenced it.  If you defined 
>P1x
> as a 5-digit interger (5I 0), then P1x would equal 49602 (=x'C1C2').
> 
> >  Why the surprise?  I expected the program to either bomb (no parms were 
> >passed to XTEST2) 
> 
> Since the CLLE program XTEST did not prototype the call to TEST2, there is no
> parameter checking -- just like in OPM.
> 
> Think for a minute what you'd expect if all the programs OPM.  Would you still
> be surprised?  That is in essence what you have here since you don't have
> prototypes on both sides to validate parameter definitions.
> 


To be honest with you, this surprised me as well.   He really should be
getting "pointer not set for location referenced" or similar message when
XTEST2 is first called.

It seems to me that the addresses of the parameters should be *NULL if
they weren't ever SET by passing parms to the procedure.  The fact that
they happened to point to the same area of memory that the previous
procedure pointed to seems like an extraordinary coincidence!

This implies that when the module is loaded into memory that it's not
initializing its variables to NULL, as I believe that it should.

I'd be interested in what Barbara & Hans have to say.


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