[fpc-pascal] NULL pointer to array of integer

Vinzent Höfler JeLlyFish.software at gmx.net
Wed Sep 13 19:39:07 CEST 2006

Jonas Maebe wrote:

> On 13 Sep 2006, at 14:00, Eduardo wrote:
>> I remember that on c a null pointer has value 0, but in ansi pascal it 
>> has value 23.
> The value of nil is not defined in the ISO Ansi Pascal standard.

Neither it is in any official C standard.

 > In FPC, nil = pointer(0) on all currently supported platforms, but in
 > principle it could be anything.

I'm making enemies now, but:

If the NIL pointer is represented by another value (like 0xFFFFF780 or 
such) on a given target platform, the integer conversion from a 
_compile-time_ constant 0 literal should still lead to a NIL representation.

Basically that would be the same behaviour as what the C-standard 

Note that this leads to a subtle difference on such platforms between 
integer literals whether they're known at compile or at runtime.


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