On Mon, 18 Jun 2012, Steven Bosscher wrote:
> For targets that do not define NO_IMPLICIT_EXTERN_C, GCC assumes that
> included system headers are implicitly wrapped in 'extern "C" {...}'.
> I could not find where this target macro was introduced, but it is
> very old (it is already mentioned in FSFChangeLog.10 for a change in
> 1995). AFAICT, today all supported targets have C++-compatible headers
May have been introduced by:
Fri Nov 5 05:48:04 1993 Richard Stallman (r...@mole.gnu.ai.mit.edu)
* cccp.c (main): Handle NO_IMPLICIT_EXTERN_C.
> (according to one comment, even hpux8 had C++-compatible system
> headers :-), so NO_IMPLICIT_EXTERN_C shouldn't be necessary anymore.
It was previously said that AIX headers needed it
<http://gcc.gnu.org/ml/gcc/2005-05/msg00381.html>. That of course was AIX
headers as of 2005; I don't know whether seven years later any version of
AIX supported by GCC trunk still needs this.
> The only target that explicitly undefines NO_IMPLICIT_EXTERN_C is
> sparc64-openbsd, and I find it hard to believe that the system headers
> on openbsd are not also already C++-compatible. Marc, could you have a
> look at this, please?
What targets (such as AIX?) did not explicitly undefine it, but did not
get a definition from any header they used either? It's quite likely some
such targets *should* have had NO_IMPLICIT_EXTERN_C defined, but not
necessarily all of them.
--
Joseph S. Myers
jos...@codesourcery.com
