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ruby--ruby/include/ruby/backward/2/assume.h

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/** \noop-*-C++-*-vi:ft=cpp
* @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 #ASSUME / #RB_LIKELY / #UNREACHABLE
*/
#include "ruby/3/config.h"
#include "ruby/3/assume.h"
#include "ruby/3/has/builtin.h"
#undef ASSUME /* Kill config.h definition */
#undef UNREACHABLE /* Kill config.h definition */
#define ASSUME RUBY3_ASSUME
#define UNREACHABLE RUBY3_UNREACHABLE()
#define UNREACHABLE_RETURN RUBY3_UNREACHABLE_RETURN
/* likely */
#if RUBY3_HAS_BUILTIN(__builtin_expect)
# define RB_LIKELY(x) (__builtin_expect(!!(x), 1))
# define RB_UNLIKELY(x) (__builtin_expect(!!(x), 0))
#else
# define RB_LIKELY(x) (x)
# define RB_UNLIKELY(x) (x)
#endif