Re: relationship between standard C and gcc compiler suite?

["Robert P. J. Day" <rpjday@mindspring.com>]

On Wed, 3 Aug 2005, Steve Graegert wrote:

> In case of GCC, including <stdbool.h> cleans up #defines and allows
> C++ compilation.  It is therefore recommended to #define these
> identifiers only when _needed_ and after including <stdbool.h>.
> <stdbool.h> is provided as an extension and, for this reason, not
> placed into the include directory of the C standard library.

ok, this is where i might be having my difficulty.  in H&S (5th ed),
p. 325, i read (emphasis added):

"Certain Standard C libraries can be considered part of the language.
The provide standard definitions and parameterization that help make C
programs more portable... These core libraries consist of the header
files ... stdbool.h, ..."

my reading of this is that stdbool.h is not an extension, it's a part
of the core.  what am i mnisreading here?

rday