std::is_move_assignable, std::is_trivially_move_assignable, std::is_nothrow_move_assignable
cppreference.com
<tbody>
</tbody>
template< class T > struct is_move_assignable; |
(1) | ( C++11) |
template< class T > struct is_trivially_move_assignable; |
(2) | ( C++11) |
template< class T > struct is_nothrow_move_assignable; |
(3) | ( C++11) |
1)
T , (.., , cv- void cv- ), - value, false. - value, std::is_assignable<T&, T&&>::value.2) , (1),
std::is_trivially_assignable<T&, T&&>3) , (1),
std::is_nothrow_assignable<T&, T&&>T , (, cv-) void . .
, , , .
, , .
<tbody> </tbody>
template< class T > inline constexpr bool is_move_assignable_v = is_move_assignable<T>::value; |
( C++17) | |
template< class T > inline constexpr bool is_trivially_move_assignable_v = is_trivially_move_assignable<T>::value; |
( C++17) | |
template< class T > inline constexpr bool is_nothrow_move_assignable_v = is_nothrow_move_assignable<T>::value; |
( C++17) | |
std::integral_constant
value [static] |
true, T , false (public static -) |
-
operator bool |
bool, value (public -) |
operator() (C++14) |
value (public -) |
value_type
|
bool
|
type
|
std::integral_constant<bool, value>
|
template< class T>
struct is_move_assignable
: std::is_assignable< typename std::add_lvalue_reference<T>::type,
typename std::add_rvalue_reference<T>::type> {};
template< class T>
struct is_trivially_move_assignable
: std::is_trivially_assignable< typename std::add_lvalue_reference<T>::type,
typename std::add_rvalue_reference<T>::type> {};
template< class T>
struct is_nothrow_move_assignable
: std::is_nothrow_assignable< typename std::add_lvalue_reference<T>::type,
typename std::add_rvalue_reference<T>::type> {};
|
std::is_move_assignable , MoveAssignable, ( MoveAssignable T&), , .
, ; MoveAssignable
#include <iostream>
#include <string>
#include <type_traits>
struct Foo { int n; };
struct NoMove {
//
// , ,
//
NoMove& operator=(const NoMove&) { return *this; }
};
int main() {
std::cout << std::boolalpha
<< "std::string ? "
<< std::is_nothrow_move_assignable<std::string>::value << '\n'
<< "int[2] ? "
<< std::is_move_assignable<int[2]>::value << '\n'
<< "Foo ? "
<< std::is_trivially_move_assignable<Foo>::value << '\n';
std::cout << std::boolalpha
<< "NoMove ? "
<< std::is_move_assignable<NoMove>::value << '\n'
<< "NoMove ? "
<< std::is_nothrow_move_assignable<NoMove>::value << '\n';
}
:
std::string ? true
int[2] ? false
Foo ? true
NoMove ? true
NoMove ? false
(C++11)(C++11)(C++11) |
, ( ) |
(C++11)(C++11)(C++11) |
, ( ) |