[PATCH] Document C++ standards

["Doug Gregor" <doug dot gregor at gmail dot com>]

This documentation patch does two things. First, it rearranges
standards.texi into per-language subsections, rather than being one
long section covering C, Objective-C, Objective-C++, and Treelang.
Second, it adds a new section for C++ to discuss our standards
support, including mentioning the experimental C++0x mode.

A wwwdocs patch is coming, which documents our C++0x support.

Okay for mainline?

:ADDPATCH doc:

 Cheers,
 Doug

2007-04-20  Douglas Gregor  <doug.gregor@gmail.com>

	* standards.texi: Re-arrange into language-specific
	subsections. Add a C++ section, documenting which standards we
	support.

Index: standards.texi
===================================================================
--- standards.texi	(revision 123994)
+++ standards.texi	(working copy)
@@ -4,6 +4,12 @@

@node Standards
@chapter Language Standards Supported by GCC
+
+For each language compiled by GCC for which there is a standard, GCC
+attempts to follow one or more versions of that standard, possibly
+with some exceptions, and possibly with some extensions.
+
+@section C language
@cindex C standard
@cindex C standards
@cindex ANSI C standard
@@ -38,10 +44,6 @@
@cindex hosted environment
@findex __STDC_HOSTED__

-For each language compiled by GCC for which there is a standard, GCC
-attempts to follow one or more versions of that standard, possibly
-with some exceptions, and possibly with some extensions.
-
GCC supports three versions of the C standard, although support for
the most recent version is not yet complete.

@@ -154,8 +156,45 @@ For references to Technical Corrigenda,
information concerning the history of C that is available online, see
@uref{http://gcc.gnu.org/readings.html}

-@c FIXME: details of C++ standard.
+@section C++ language
+
+GCC supports the ISO C++ standard (1998) and contains experimental
+support for the upcoming ISO C++ standard (200x).
+
+The original ISO C++ standard was published as the ISO standard (ISO/IEC
+14882:1998) and amended by a Technical Corrigenda published in 2003
+(ISO/IEC 14882:2003). These standards are referred to as C++98 and
+C++03, respectively. GCC implements the majority of C++98 (@code{export}
+is a notable exception) and most of the changes in C++03.  To select
+this standard in GCC, use one of the options @option{-ansi} or
+@option{-std=c++98}; to obtain all the diagnostics required by the
+standard, you should also specify @option{-pedantic} (or
+@option{-pedantic-errors} if you want them to be errors rather than
+warnings).
+
+The ISO C++ committee is working on a new ISO C++ standard, dubbed
+C++0x, that is intended to be published by 2009. C++0x contains several
+changes to the C++ language, some of which have been implemented in an
+experimental C++0x mode in GCC. The C++0x mode in GCC tracks the draft
+working paper for the C++0x standard; the latest working paper is
+available on the ISO C++ committee's web site at
+@uref{http://www.open-std.org/jtc1/sc22/wg21/}. For information
+regarding the C++0x features available in the experimental C++0x mode,
+see @uref{http://gcc.gnu.org/gcc-4.3/cxx0x_status.html}. To select this
+standard in GCC, use the option @option{-std=c++0x}; to obtain all the
+diagnostics required by the standard, you should also specify
+@option{-pedantic} (or @option{-pedantic-errors} if you want them to be
+errors rather than warnings).
+
+By default, GCC provides some extensions to the C++ language; @xref{C++
+Dialect Options,Options Controlling C++ Dialect}.  Use of the
+@option{-std} option listed above will disable these extensions.  You
+may also select an extended version of the C++ language explicitly with
+@option{-std=gnu++98} (for C++98 with GNU extensions) or
+@option{-std=gnu++0x} (for C++0x with GNU extensions).  The default, if
+no C++ language dialect options are given, is @option{-std=gnu++98}.

+@section Objective-C and Objective-C++ languages
@cindex Objective-C
@cindex Objective-C++

@@ -177,6 +216,7 @@ and
have additional useful information.
@end itemize

+@section Treelang language
@cindex treelang
There is no standard for treelang, which is a sample language front end
for GCC@.  Its only purpose is as a sample for people wishing to write a