The std::is_move_assignable template of C++ STL is present in the <type_traits> header file. The std::is_move_assignable template of C++ STL is used to check whether the T is a move assignable type(that can be assigned an rvalue reference of the same type) or not. It return the boolean value true if T is move assignable type otherwise return false.
Header File:
#include<type_traits>
Template Class:
template <class T> struct is_move_assignable;
Syntax:
std::is_move_assignable<T>::value
Parameters: The template std::is_move_assignable accepts a single parameter T(Trait class) to check whether T is move assignable or not.
Return Value: This template returns a boolean variable as shown below:
- True: If the type T is a move assignable type.
- False: If the type T is not a move assignable type.
Below is the program to illustrates the std::is_move_assignable template in C/C++:
Program:
// C++ program to illustrate // std::is_move_assignable #include <bits/stdc++.h> #include <type_traits> using namespace std;
// Declare structures struct A {
}; struct B {
B& operator=(B&) = delete ;
}; struct C {
~C() = delete ;
}; // Driver Code int main()
{ cout << boolalpha;
// Check if int is move
// assignable or not
cout << "int: "
<< is_move_assignable< int >::value
<< endl;
// Check if struct A is move
// assignable or not
cout << "struct A: "
<< is_move_assignable<A>::value
<< endl;
// Check if struct B is move
// assignable or not
cout << "struct B: "
<< is_move_assignable<B>::value
<< endl;
// Check if struct C is move
// assignable or not
cout << "struct C: "
<< is_move_assignable<C>::value
<< endl;
// Declare an map
unordered_multimap< int , string> m;
m.insert({ 1, "GfG" });
// Check if map m is move
// assignable or not?
cout << "Map m: "
<< is_move_assignable< decltype (*m.begin())>::value;
return 0;
} |
int: true struct A: true struct B: false struct C: true Map m: true
Reference: http://www.cplusplus.com/reference/type_traits/is_move_assignable/