RESTinio

compiler_features.hpp
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1/*
2 * RESTinio
3 */
4
12#pragma once
13
14#include <utility>
15
16// Try to use __has_cpp_attribute if it is supported.
17#if defined(__has_cpp_attribute)
18 // clang-4 and clang-5 produce warnings when [[nodiscard]]
19 // is used with -std=c++11 and -std=c++14.
20 #if __has_cpp_attribute(nodiscard) && \
21 !(defined(__clang__) && __cplusplus < 201703L)
22 #define RESTINIO_NODISCARD [[nodiscard]]
23 #endif
24
25 #if __has_cpp_attribute(fallthrough) && \
26 !(defined(__clang__) && __cplusplus < 201703L)
27 #define RESTINIO_FALLTHROUGH [[fallthrough]]
28 #endif
29#endif
30
31// Handle the result of __has_cpp_attribute.
32#if !defined( RESTINIO_NODISCARD )
33 #define RESTINIO_NODISCARD
34#endif
35
36#if !defined( RESTINIO_FALLTHROUGH )
37 #define RESTINIO_FALLTHROUGH
38#endif
39
60#define RESTINIO_ENSURE_NOEXCEPT_CALL(expr) \
61 static_assert(noexcept(expr), "this call is expected to be noexcept: " #expr); \
62 expr
63
89#define RESTINIO_STATIC_ASSERT_NOEXCEPT(expr) \
90 static_assert(noexcept(expr), #expr " is expected to be noexcept" )
91
116#define RESTINIO_STATIC_ASSERT_NOT_NOEXCEPT(expr) \
117 static_assert(!noexcept(expr), #expr " is not expected to be noexcept" )
118
119 namespace restinio
120{
121
122 namespace static_if_details
123{
124
125 template< bool Condition >
126 struct static_if_impl;
127
128 template<>
129 struct static_if_impl<true>
130{
131 template<typename If_Part, typename Else_Part>
132 static decltype(auto)
133 call( If_Part && if_part, Else_Part && )
134 {
135 return if_part();
136 }
137};
138
139 template<>
140 struct static_if_impl<false>
141{
142 template<typename If_Part, typename Else_Part>
143 static decltype(auto)
144 call( If_Part &&, Else_Part && else_part )
145 {
146 return else_part();
147 }
148};
149
150} /* namespace static_if_details */
151
152//
153// static_if_else
154//
174 template< bool Condition, typename If_Part, typename Else_Part >
175 decltype(auto)
176 static_if_else( If_Part && if_part, Else_Part && else_part )
177{
178 return static_if_details::static_if_impl<Condition>::call(
179 std::forward<If_Part>(if_part),
180 std::forward<Else_Part>(else_part) );
181}
182
183} /* namespace restinio */
184
restinio
Definition: asio_include.hpp:21
restinio::static_if_else
decltype(auto) static_if_else(If_Part &&if_part, Else_Part &&else_part)
An emulation of if constexpr for C++14.
Definition: compiler_features.hpp:176
restinio::static_if_details::static_if_impl< false >::call
static decltype(auto) call(If_Part &&, Else_Part &&else_part)
Definition: compiler_features.hpp:144
restinio::static_if_details::static_if_impl< true >::call
static decltype(auto) call(If_Part &&if_part, Else_Part &&)
Definition: compiler_features.hpp:133
restinio::static_if_details::static_if_impl
Definition: compiler_features.hpp:126