It is a design flaw but it has been around a long time.  nil is Pascal's NULL.  All of the Mac OS's system interfaces were originally defined as Pascal and nil has been in the system headers since 1984.

Attempting to #undef a system constant is doomed to failure.  It would be very sensitive to include ordering.  Think of it like trying to redefine NULL.

Jeremy suggests in another email that boost::nil be renamed boost::null_pointer or something like that.  I believe this is the route to take.

Chris

> -----Original Message-----
> From: jk@steel.orel.ru [mailto:jk@steel.orel.ru]
> Sent: Friday, June 08, 2001 9:44 AM
> To: boost@yahoogroups.com
> Subject: Re: [boost] boost::nil
>
>
> 8 Jun 2001 17:23:45 +0400 Chris Little написал:
> >On a Mac, nil is a preprocessor macro included in the system
> headers as a
>
> Exactly that way, lowercase macro? Then this is BIG design
> flaw in MacOS.
>
> >legacy of the days when the OS had a Pascal interface.
>
> How about something like
>
> #ifdef nil
> #undef nil
> void * const nil=0; // or what appropriate, in global namespace.
> #endif
>
> somewhere in config.hpp?
>
> --
> jk
>