* c-cppbuiltin.c (c_cpp_builtins): Do not define __GXX_WEAK__ to 1

	if !flag_weak.
	* doc/cpp.texi (__DEPRECATED): Document.
	(__EXCEPTIONS): Likewise.
	(__GXX_WEAK__): Likewise.

	* g++.dg/cpp/weak.C: New test.


git-svn-id: svn+ssh://gcc.gnu.org/svn/gcc/trunk@99080 138bc75d-0d04-0410-961f-82ee72b054a4

1 files changed, 20 insertions, 0 deletions

diff --git a/gcc/doc/cpp.texi b/gcc/doc/cpp.texi
index 02cb4b8d200..71bd4ee2677 100644
--- a/gcc/doc/cpp.texi
+++ b/gcc/doc/cpp.texi
@@ -2081,11 +2081,31 @@ respectively.  They exist to make the standard header given numerical limits
 work correctly.  You should not use these macros directly; instead, include
 the appropriate headers.
 
+@item __DEPRECATED
+This macro is defined, with value 1, when compiling a C++ source file
+with warnings about deprecated constructs enabled.  These warnings are
+enabled by default, but can be disabled with @option{-Wno-deprecated}.
+
+@item __EXCEPTIONS
+This macro is defined, with value 1, when compiling a C++ source file
+with exceptions enabled.  If @option{-fno-exceptions} was used when
+compiling the file, then this macro will not be defined.
+
 @item __USING_SJLJ_EXCEPTIONS__
 This macro is defined, with value 1, if the compiler uses the old
 mechanism based on @code{setjmp} and @code{longjmp} for exception
 handling.
 
+@item __GXX_WEAK__
+This macro is defined when compiling a C++ source file.  It has the
+value 1 if the compiler will use weak symbols, COMDAT sections, or
+other similar techniques to collapse symbols with ``vague linkage''
+that are defined in multiple translation units.  If the compiler will
+not collapse such symbols, this macro is defined with value 0.  In
+general, user code should not need to make use of this macro; the
+purpose of this macro is to ease implementation of the C++ runtime
+library provided with G++.
+
 @item __NEXT_RUNTIME__
 This macro is defined, with value 1, if (and only if) the NeXT runtime
 (as in @option{-fnext-runtime}) is in use for Objective-C@.  If the GNU