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- /*
- @Copyright Barrett Adair 2015-2017
- Distributed under the Boost Software License, Version 1.0.
- (See accompanying file LICENSE.md or copy at http://boost.org/LICENSE_1_0.txt)
- */
- #ifndef BOOST_CLBL_TRTS_RESULT_OF_HPP
- #define BOOST_CLBL_TRTS_RESULT_OF_HPP
- #include <boost/callable_traits/detail/core.hpp>
- namespace boost { namespace callable_traits {
- BOOST_CLBL_TRTS_DEFINE_SFINAE_ERROR_ORIGIN(return_type)
- BOOST_CLBL_TRTS_SFINAE_MSG(return_type, unable_to_determine_return_type)
- //[ return_type_hpp
- /*`
- [section:ref_return_type return_type]
- [heading Header]
- ``#include <boost/callable_traits/return_type.hpp>``
- [heading Definition]
- */
- template<typename T>
- using return_type_t = //see below
- //<-
- detail::try_but_fail_if_invalid<
- typename detail::traits<detail::shallow_decay<T>>::return_type,
- unable_to_determine_return_type>;
- namespace detail {
- template<typename T, typename = std::false_type>
- struct return_type_impl {};
- template<typename T>
- struct return_type_impl <T, typename std::is_same<
- return_type_t<T>, detail::dummy>::type>
- {
- using type = return_type_t<T>;
- };
- }
- //->
- template<typename T>
- struct return_type : detail::return_type_impl<T> {};
- //<-
- }} // namespace boost::callable_traits
- //->
- /*`
- [heading Constraints]
- * `T` must be one of the following:
- * function
- * function pointer
- * function reference
- * member function pointer
- * member data pointer
- * user-defined type with a non-overloaded `operator()`
- * type of a non-generic lambda
- [heading Behavior]
- * When the constraints are violated, a substitution failure occurs.
- * The aliased type is the return type of `T`.
- [heading Input/Output Examples]
- [table
- [[`T`] [`return_type_t<T, std::tuple>`]]
- [[`void()`] [`void`]]
- [[`float(*)()`] [`float`]]
- [[`const char*(&)()`] [`const char *`]]
- [[`int(foo::*)() const`] [`int`]]
- [[`int`] [(substitution failure)]]
- [[`int (*const)()`] [(substitution failure)]]
- ]
- [heading Example Program]
- [import ../example/return_type.cpp]
- [return_type]
- [endsect]
- */
- //]
- #endif // #ifndef BOOST_CLBL_TRTS_RESULT_OF_HPP
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