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. Richard.
