39 lines
1.8 KiB
C++
39 lines
1.8 KiB
C++
#ifndef RBIMPL_HAS_C_ATTRIBUTE_H /*-*-C++-*-vi:se ft=cpp:*/
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#define RBIMPL_HAS_C_ATTRIBUTE_H
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/**
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* @file
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* @author Ruby developers <ruby-core@ruby-lang.org>
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* @copyright This file is a part of the programming language Ruby.
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* Permission is hereby granted, to either redistribute and/or
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* modify this file, provided that the conditions mentioned in the
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* file COPYING are met. Consult the file for details.
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* @warning Symbols prefixed with either `RBIMPL` or `rbimpl` are
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* implementation details. Don't take them as canon. They could
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* rapidly appear then vanish. The name (path) of this header file
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* is also an implementation detail. Do not expect it to persist
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* at the place it is now. Developers are free to move it anywhere
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* anytime at will.
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* @note To ruby-core: remember that this header can be possibly
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* recursively included from extension libraries written in C++.
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* Do not expect for instance `__VA_ARGS__` is always available.
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* We assume C99 for ruby itself but we don't assume languages of
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* extension libraries. They could be written in C++98.
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* @brief Defines #RBIMPL_HAS_C_ATTRIBUTE.
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*/
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/** Wraps (or simulates) `__has_c_attribute`. */
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#if defined(__cplusplus)
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# /* Makes no sense. */
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# define RBIMPL_HAS_C_ATTRIBUTE(_) 0
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#elif defined(__has_c_attribute)
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# define RBIMPL_HAS_C_ATTRIBUTE(_) __has_c_attribute(_)
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#else
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# /* As of writing everything that lacks __has_c_attribute also completely
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# * lacks C2x attributes as well. Might change in future? */
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# define RBIMPL_HAS_C_ATTRIBUTE(_) 0
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#endif
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#endif /* RBIMPL_HAS_C_ATTRIBUTE_H */
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