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Diffstat (limited to 'include/ruby/impl/attr/nodiscard.h')
| -rw-r--r-- | include/ruby/impl/attr/nodiscard.h | 45 |
1 files changed, 45 insertions, 0 deletions
diff --git a/include/ruby/impl/attr/nodiscard.h b/include/ruby/impl/attr/nodiscard.h new file mode 100644 index 0000000000..6168bb9002 --- /dev/null +++ b/include/ruby/impl/attr/nodiscard.h @@ -0,0 +1,45 @@ +#ifndef RUBY3_ATTR_NODISCARD_H /*-*-C++-*-vi:se ft=cpp:*/ +#define RUBY3_ATTR_NODISCARD_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 Defines #RUBY3_ATTR_NODISCARD. + */ +#include "ruby/3/has/attribute.h" +#include "ruby/3/has/c_attribute.h" +#include "ruby/3/has/cpp_attribute.h" + +/** + * Wraps (or simulates) `[[nodiscard]]`. In C++ (at least since C++20) a + * nodiscard attribute can have a message why the result shall not be ignoed. + * However GCC attribute and SAL annotation cannot take them. + */ +#if RUBY3_HAS_CPP_ATTRIBUTE(nodiscard) +# define RUBY3_ATTR_NODISCARD() [[nodiscard]] +#elif RUBY3_HAS_C_ATTRIBUTE(nodiscard) +# define RUBY3_ATTR_NODISCARD() [[nodiscard]] +#elif RUBY3_HAS_ATTRIBUTE(warn_unused_result) +# define RUBY3_ATTR_NODISCARD() __attribute__((__warn_unused_result__)) +#elif defined(_Check_return_) +# /* Take SAL definition. */ +# define RUBY3_ATTR_NODISCARD() _Check_return_ +#else +# define RUBY3_ATTR_NODISCARD() /* void */ +#endif + +#endif /* RUBY3_ATTR_NODISCARD_H */ |