This patch is for PR4225, another ancient C++ documentation issue, in
which a user expressed surprise at the implicit extern "C" block the
preprocessor added to system headers specified via CPLUS_INCLUDE_PATH.
Presently RS/6000 AIX is the only remaining target that gives this
special treatment to system headers; see
https://gcc.gnu.org/ml/gcc-patches/2018-07/msg00116.html
-Sandra
2018-11-17 Sandra Loosemore <san...@codesourcery.com>
PR c++/4225
gcc/
* doc/cpp.texi (System Headers): Add note about implicit
extern "C" block on targets that define SYSTEM_IMPLICIT_EXTERN_C.
Index: gcc/doc/cpp.texi
===================================================================
--- gcc/doc/cpp.texi (revision 266238)
+++ gcc/doc/cpp.texi (working copy)
@@ -1131,6 +1131,9 @@ header, no matter where it was found. C
system_header}} has no effect in the primary source file.
@end itemize
+On some targets, such as RS/6000 AIX, GCC implicitly surrounds all
+system headers with an @samp{extern "C"} block when compiling as C++.
+
@node Macros
@chapter Macros
