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ruby--ruby/include/ruby/3/dllexport.h
卜部昌平 4ff3f20540 add #include guard hack
According to MSVC manual (*1), cl.exe can skip including a header file
when that:

- contains #pragma once, or
- starts with #ifndef, or
- starts with #if ! defined.

GCC has a similar trick (*2), but it acts more stricter (e. g. there
must be _no tokens_ outside of #ifndef...#endif).

Sun C lacked #pragma once for a looong time.  Oracle Developer Studio
12.5 finally implemented it, but we cannot assume such recent version.

This changeset modifies header files so that each of them include
strictly one #ifndef...#endif.  I believe this is the most portable way
to trigger compiler optimizations. [Bug #16770]

*1: https://docs.microsoft.com/en-us/cpp/preprocessor/once
*2: https://gcc.gnu.org/onlinedocs/cppinternals/Guard-Macros.html
2020-04-13 16:06:00 +09:00

92 lines
3.5 KiB
C++

#ifndef RUBY3_DLLEXPORT_H /*-*-C++-*-vi:se ft=cpp:*/
#define RUBY3_DLLEXPORT_H
/**
* @file
* @author Ruby developers <ruby-core@ruby-lang.org>
* @copyright This file is a part of the programming language Ruby.
* Permission is hereby granted, to either redistribute and/or
* modify this file, provided that the conditions mentioned in the
* file COPYING are met. Consult the file for details.
* @warning Symbols prefixed with either `RUBY3` or `ruby3` are
* implementation details. Don't take them as canon. They could
* rapidly appear then vanish. The name (path) of this header file
* is also an implementation detail. Do not expect it to persist
* at the place it is now. Developers are free to move it anywhere
* anytime at will.
* @note To ruby-core: remember that this header can be possibly
* recursively included from extension libraries written in C++.
* Do not expect for instance `__VA_ARGS__` is always available.
* We assume C99 for ruby itself but we don't assume languages of
* extension libraries. They could be written in C++98.
* @brief Tewaking visibility of C variables/functions.
*/
#include "ruby/3/config.h"
#include "ruby/3/compiler_is.h"
/* For MinGW, we need __declspec(dllimport) for RUBY_EXTERN on MJIT.
mswin's RUBY_EXTERN already has that. See also: win32/Makefile.sub */
#undef RUBY_EXTERN
#if defined(MJIT_HEADER) && defined(_WIN32)
# define RUBY_EXTERN extern __declspec(dllimport)
#elif defined(RUBY_EXPORT)
# define RUBY_EXTERN extern
#elif defined(_WIN32)
# define RUBY_EXTERN extern __declspec(dllimport)
#else
# define RUBY_EXTERN extern
#endif
#ifndef RUBY_SYMBOL_EXPORT_BEGIN
# define RUBY_SYMBOL_EXPORT_BEGIN /* begin */
#endif
#ifndef RUBY_SYMBOL_EXPORT_END
# define RUBY_SYMBOL_EXPORT_END /* end */
#endif
#ifndef RUBY_FUNC_EXPORTED
# define RUBY_FUNC_EXPORTED /* void */
#endif
/* These macros are used for functions which are exported only for MJIT
and NOT ensured to be exported in future versions. */
#if ! defined(MJIT_HEADER)
# define MJIT_FUNC_EXPORTED RUBY_FUNC_EXPORTED
#elif ! RUBY3_COMPILER_IS(MSVC)
# define MJIT_FUNC_EXPORTED RUBY_FUNC_EXPORTED
#else
# define MJIT_FUNC_EXPORTED static
#endif
#define MJIT_SYMBOL_EXPORT_BEGIN RUBY_SYMBOL_EXPORT_BEGIN
#define MJIT_SYMBOL_EXPORT_END RUBY_SYMBOL_EXPORT_END
/* On mswin, MJIT header transformation can't be used since cl.exe can't output
preprocessed output preserving macros. So this `MJIT_STATIC` is needed
to force non-static function to static on MJIT header to avoid symbol conflict. */
#ifdef MJIT_HEADER
# define MJIT_STATIC static
#else
# define MJIT_STATIC
#endif
/** Shortcut macro equivalent to `RUBY_SYMBOL_EXPORT_BEGIN extern "C" {`.
* \@shyouhei finds it handy. */
#if defined(__DOXYGEN__)
# define RUBY3_SYMBOL_EXPORT_BEGIN() /* void */
#elif defined(__cplusplus)
# define RUBY3_SYMBOL_EXPORT_BEGIN() RUBY_SYMBOL_EXPORT_BEGIN extern "C" {
#else
# define RUBY3_SYMBOL_EXPORT_BEGIN() RUBY_SYMBOL_EXPORT_BEGIN
#endif
/** Counterpart of #RUBY3_SYMBOL_EXPORT_BEGIN */
#if defined(__DOXYGEN__)
# define RUBY3_SYMBOL_EXPORT_END() /* void */
#elif defined(__cplusplus)
# define RUBY3_SYMBOL_EXPORT_END() } RUBY_SYMBOL_EXPORT_END
#else
# define RUBY3_SYMBOL_EXPORT_END() RUBY_SYMBOL_EXPORT_END
#endif
#endif /* RUBY3_DLLEXPORT_H */