While updating our C++17 features to add the new std::invoke_result
trait I got annoyed with the repetition in std::_Not_fn, as it makes
it hard to check it's defined correctly. Specifically, we need to
repeat the cv-qualifier and ref-qualifiers in multiple places in each
overload.
This introduces a macro that is expanded with one of "&" or "const &"
or "&&" or "const &&" and so ensures it's used consistently.
This only affects C++17 std::not_fn and std::experimental::not_fn so
I'm committing it now.
* include/std/functional (_Not_fn): Define macro to simplify
repetitive function definitions.
Tested powerpc64le-linux, committed to trunk.
commit 0eb6e44bcabb995d29b5569f27f221dd92027c00
Author: Jonathan Wakely <jwak...@redhat.com>
Date: Thu Mar 9 20:15:55 2017 +0000
Define macro to simplify std::_Not_fn definition
* include/std/functional (_Not_fn): Define macro to simplify
repetitive function definitions.
diff --git a/libstdc++-v3/include/std/functional
b/libstdc++-v3/include/std/functional
index ea36dd0..366a7fb 100644
--- a/libstdc++-v3/include/std/functional
+++ b/libstdc++-v3/include/std/functional
@@ -902,15 +902,12 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
template<typename _Fn>
class _Not_fn
{
- template<typename _Tp>
- using __is_nothrow_negatable
- = __bool_constant<noexcept(!std::declval<_Tp>())>;
-
template<typename _Fn2, typename... _Args>
- using __noexcept_cond = __and_<
- __is_nothrow_callable<_Fn2(_Args&&...)>,
- __is_nothrow_negatable<result_of_t<_Fn2(_Args&&...)>>
- >;
+ using __inv_res_t = result_of_t<_Fn2(_Args&&...)>;
+
+ template<typename _Tp>
+ static decltype(!std::declval<_Tp>())
+ _S_not() noexcept(noexcept(!std::declval<_Tp>()));
public:
template<typename _Fn2>
@@ -921,39 +918,23 @@ _GLIBCXX_MEM_FN_TRAITS(&&, false_type, true_type)
_Not_fn(_Not_fn&& __fn) = default;
~_Not_fn() = default;
- template<typename... _Args>
- auto
- operator()(_Args&&... __args) &
- noexcept(__noexcept_cond<_Fn&, _Args&&...>::value)
- -> decltype(!std::declval<result_of_t<_Fn&(_Args&&...)>>())
- { return !std::__invoke(_M_fn, std::forward<_Args>(__args)...); }
-
- template<typename... _Args>
- auto
- operator()(_Args&&... __args) const &
- noexcept(__noexcept_cond<const _Fn&, _Args&&...>::value)
- -> decltype(!std::declval<result_of_t<const _Fn&(_Args&&...)>>())
- { return !std::__invoke(_M_fn, std::forward<_Args>(__args)...); }
-
- template<typename... _Args>
- auto
- operator()(_Args&&... __args) &&
- noexcept(__noexcept_cond<_Fn&&, _Args&&...>::value)
- -> decltype(!std::declval<result_of_t<_Fn&&(_Args&&...)>>())
- {
- return !std::__invoke(std::move(_M_fn),
- std::forward<_Args>(__args)...);
- }
-
- template<typename... _Args>
- auto
- operator()(_Args&&... __args) const &&
- noexcept(__noexcept_cond<const _Fn&&, _Args&&...>::value)
- -> decltype(!std::declval<result_of_t<const _Fn&&(_Args&&...)>>())
- {
- return !std::__invoke(std::move(_M_fn),
- std::forward<_Args>(__args)...);
+ // Macro to define operator() with given cv-qualifiers ref-qualifiers,
+ // forwarding _M_fn and the function arguments with the same qualifiers,
+ // and deducing the return type and exception-specification.
+#define _GLIBCXX_NOT_FN_CALL_OP( _QUALS ) \
+ template<typename... _Args> \
+ decltype(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>()) \
+ operator()(_Args&&... __args) _QUALS \
+ noexcept(noexcept(_S_not<__inv_res_t<_Fn _QUALS, _Args...>>())) \
+ { \
+ return !std::__invoke(std::forward< _Fn _QUALS >(_M_fn), \
+ std::forward<_Args>(__args)...); \
}
+ _GLIBCXX_NOT_FN_CALL_OP( & )
+ _GLIBCXX_NOT_FN_CALL_OP( const & )
+ _GLIBCXX_NOT_FN_CALL_OP( && )
+ _GLIBCXX_NOT_FN_CALL_OP( const && )
+#undef _GLIBCXX_NOT_FN_CALL
private:
_Fn _M_fn;
