🚀 go-pugleaf

In article <4d6673$8to@mailgate.bridgewater.ne.hcc.com>,
John W Kennedy <kennedy1@bwmail1.hcc.com> wrote:
>Is there an official statement as to what __STDC__ means?  Does it mean "This
>compiler (in its current operating mode) fully supports ANSI Standard C," or
>does it mean "This compiler (in its current operating mode) disallows all
>extensions to ANSI Standard C."?  In my opinion, common practice and the
>Rationale both support the former, rather than the latter, but is
>there an official ruling?

__STDC__ is almost meaningless.  For a standard C compiler, it is a synonym
for 1.  A compiler that is not standard conformant is free to define __STDC__
to be 1, since the C standard affects only conformant compilers.

The setting of __STDC__ does not prohibit extensions.  The C standard allows
arbitrary extensions provided the compiler issues at least one diagnostic
message for each program that violates a syntax rule or constraint.

The Solaris 2.4 and 2.5 header files use a magic symbol to allow access
to parts of the headers that otherwise would not be accessible in strict
compliant mode.  If the symbol __EXTENSIONS__ is #defined before #including
a header the entire header is read.  No strictly conforming program is
allowed to #define __EXTENSIONS__, but the prohibition is not a constraint.
Therefore, no error message need be issued.

					Sincerely,
					Robert Corbett