Date:	Thu, 26 Mar 1998 14:50:43 +0100 (MET)
Message-Id:	<199803261350.OAA25048@tyr.diku.dk>
From:	Morten Welinder <terra AT diku DOT dk>
To:	djgpp-workers AT delorie DOT com
In-reply-to:	<351A0E4B.57F8@rug.ac.be> (message from Vik Heyndrickx on Thu, 26
	Mar 1998 09:14:03 +0100)
Subject:	Re: NULL redefined! :(
References:	<199803252349 DOT SAA09833 AT delorie DOT com> <351A0E4B DOT 57F8 AT rug DOT ac DOT be>

__null was introduced by the EGCS people because...

1. "0" doesn't work well on machine for which
    sizeof (int) != sizeof (void *).
2. "0L" has similar problems.
3. "((void*)0)" doesn't work in C++ because you would have to go
   cast it all the time.

__null is supposed to be a magic r-value that...

* works as "0" when compared to any pointer or integer.
* has the size of pointers (and thus looks like "((void*)0)" when
  passed.

The only place it should make a difference is with the definition
of NULL because the pre-processor doesn't know about __null's
semantics.

Morten

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