#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 */