On Sun, Jun 17, 2012 at 6:58 AM, Richard Guenther <richard.guent...@gmail.com> wrote: > On Sat, Jun 16, 2012 at 8:47 PM, Gabriel Dos Reis > <g...@integrable-solutions.net> wrote: >> On Sat, Jun 16, 2012 at 3:54 AM, Duncan Sands <baldr...@free.fr> wrote: >>> Hi, >>> >>> >>>>> If ENABLE_BUILD_WITH_CXX is defined, then GCC itself is built with C++, >>>>> and we want a C++ signature for functions. If it is not defined, then >>>>> GCC itself is not built with C++, and we want (and must have) a C >>>>> signature. >>>>> >>>>> I suppose we would decide that fancy_abort always uses a C signature, >>>>> but that seems odd. >>>>> >>>>> Ian >>>> >>>> >>>> I guess the issue is when people care only about C plugins, yet >>>> fancy_abort >>>> get implicitly exported with a C++ linkage. >>>> >>>> I suspect this goes back to the eternal question: what do we consider as >>>> part of the public GCC public API (no, Basile, I am not suggesting to have >>>> the same discussion again.) >>> >>> >>> if the following are to hold >>> >>> (1) fancy_abort is declared in system.h >>> (2) system.h should not be wrapped in extern "C" when included from a >>> plugin, >>> (3) it should be valid to include it from plugins compiled as C or as C++, >>> (4) fancy_abort should use the same linkage as GCC, i.e. C when GCC built as >>> C, >>> C++ when built as C++ (aka ENABLE_BUILD_WITH_CXX). >>> >>> then something like the following seems inevitable: >>> >>> #ifdef ENABLE_BUILD_WITH_CXX >>> #ifdef __cplusplus >>> extern void fancy_abort(const char *, int, const char *) ATTRIBUTE_NORETURN; >>> #else >>> extern void _Z11fancy_abortPKciS0_(const char *, int, const char *) >>> ATTRIBUTE_NORETURN; >>> #endif >>> #else >>> #ifdef __cplusplus >>> extern "C" void fancy_abort(const char *, int, const char *) >>> ATTRIBUTE_NORETURN; >>> #else >>> extern void fancy_abort(const char *, int, const char *) ATTRIBUTE_NORETURN; >>> #endif >>> #endif >>> >>> That's pretty nasty. But to avoid the nastiness one of (1) - (4) needs to >>> be >>> dropped. Which one? >>> >>> Ciao, Duncan. >> >> It is not just nasty; it is fragile. >> I think we should just give fancy_abort a C language specification. > > No, I think we should make system.h what system.h is about - include > all system headers. > > declaring fancy_abort with either linkage is not part of "inlude > system headers" and thus > should not be done inside system.h.
but system.h is not just including system headers.
