Re: [PATCH] Building Git on Tru64

From: Jakub Narebski <jnareb@gmail.com>
Date: Apr 15, 2010, 21:24 UTC
Message-ID: <m34ojcfly1.fsf@localhost.localdomain>
In-Reply-To: <1271360809.25304.1370186353@webmail.messagingengine.com>

"Daniel Richard G." <skunk@iSKUNK.ORG> writes:

Show 10 quoted lines

> On Thu, 2010 Apr 15 21:29+0200, Alex Riesen wrote:
> >
> > That one may be better handled at one place (git-compat-util.h?) with
> > something like:
> >
> >   #ifdef Tru64
> >   #define MAP_FAILED ((void *)MAP_FAILED)
> >   #endif
> 
> I agree with the sentiment, but you can't have a macro refer to itself

It can.  From (cpp.info)

  3.10.5 Self-Referential Macros
  ------------------------------

  A "self-referential" macro is one whose name appears in its definition.
  Recall that all macro definitions are rescanned for more macros to
  replace.  If the self-reference were considered a use of the macro, it
  would produce an infinitely large expansion.  To prevent this, the
  self-reference is not considered a macro call.  It is passed into the
  preprocessor output unchanged.

  [...]

     One common, useful use of self-reference is to create a macro which
  expands to itself.  If you write

       #define EPERM EPERM

-- 
Jakub Narebski
Poland
ShadeHawk on #git