[Bug c++/30348] '#define false FALSE' undefines '#define FALSE false'

["gdr at integrable-solutions dot net" <gcc-bugzilla at gcc dot gnu dot org>]

------- Comment #6 from gdr at integrable-solutions dot net  2007-01-02 12:05 -------
Subject: Re:  '#define false FALSE' undefines '#define FALSE false'

"pinskia at gcc dot gnu dot org" <gcc-bugzilla@gcc.gnu.org> writes:

| ------- Comment #1 from pinskia at gcc dot gnu dot org  2007-01-01 22:34
-------
| so what is happening here is the following:
| 
| #define FALSE false
| #define false FALSE
| 
| bool a = FALSE;
| 
| So we get again:
| bool a = FALSE;
| 
| 
| This is the same problem as:
| int b;
| 
| #define a b
| #define b a
| 
| int main() {
|   int test2 = a;
| }
| 
| also true/false are not defined in C++ but rather they are keywords

`true' and `false' have special meanings, in C++, during
pre-processing phases.  They can be used in the condition for
conditional inclusion, for example.  Consequently, I don't think it is
valid to 

   #define false something

just like

   #define 0 something

would be invalid.

-- Gaby


-- 


http://gcc.gnu.org/bugzilla/show_bug.cgi?id=30348