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Re: Remove TRUE and FALSE


Fergus Henderson <fjh@cs.mu.oz.au> writes:

> I agree that <stdbool.h> (with autoconf'd replacement if need be) would
> be a nice thing to move to.

This is what we're doing for INN.  It's trivial to do for true and false,
somewhat more difficult for bool since unfortunately some systems have
gone off and defined their own bool in various headers.

Perl uses the following logic to handle defining bool (note that they use
TRUE and FALSE still, not true and false):

/* XXX Configure ought to have a test for a boolean type, if I can
   just figure out all the headers such a test needs.
   Andy Dougherty       August 1996
*/
/* bool is built-in for g++-2.6.3 and later, which might be used
   for extensions.  <_G_config.h> defines _G_HAVE_BOOL, but we can't
   be sure _G_config.h will be included before this file.  _G_config.h
   also defines _G_HAVE_BOOL for both gcc and g++, but only g++
   actually has bool.  Hence, _G_HAVE_BOOL is pretty useless for us.
   g++ can be identified by __GNUG__.
   Andy Dougherty       February 2000
*/
#ifdef __GNUG__         /* GNU g++ has bool built-in */
#  ifndef HAS_BOOL
#    define HAS_BOOL 1
#  endif
#endif

/* The NeXT dynamic loader headers will not build with the bool macro
   So declare them now to clear confusion.
*/
#if defined(NeXT) || defined(__NeXT__)
# undef FALSE
# undef TRUE
  typedef enum bool { FALSE = 0, TRUE = 1 } bool;
# define ENUM_BOOL 1
# ifndef HAS_BOOL
#  define HAS_BOOL 1
# endif /* !HAS_BOOL */
#endif /* NeXT || __NeXT__ */

#ifndef HAS_BOOL
# if defined(UTS) || defined(VMS)
#  define bool int
# else
#  define bool char
# endif
# define HAS_BOOL 1
#endif

-- 
Russ Allbery (rra@stanford.edu)             <http://www.eyrie.org/~eagle/>


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