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Editing: nodiscard.h
#ifndef RBIMPL_ATTR_NODISCARD_H /*-*-C++-*-vi:se ft=cpp:*/ #define RBIMPL_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 `RBIMPL` or `rbimpl` 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 #RBIMPL_ATTR_NODISCARD. */ #include "ruby/internal/has/attribute.h" #include "ruby/internal/has/c_attribute.h" #include "ruby/internal/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 ignored. * However GCC attribute and SAL annotation cannot take them. */ #if RBIMPL_HAS_CPP_ATTRIBUTE(nodiscard) # define RBIMPL_ATTR_NODISCARD() [[nodiscard]] #elif RBIMPL_HAS_C_ATTRIBUTE(nodiscard) # define RBIMPL_ATTR_NODISCARD() [[nodiscard]] #elif RBIMPL_HAS_ATTRIBUTE(warn_unused_result) # define RBIMPL_ATTR_NODISCARD() __attribute__((__warn_unused_result__)) #elif defined(_Check_return_) # /* Take SAL definition. */ # define RBIMPL_ATTR_NODISCARD() _Check_return_ #else # define RBIMPL_ATTR_NODISCARD() /* void */ #endif #endif /* RBIMPL_ATTR_NODISCARD_H */
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