The std::is_nothrow_copy_assignable template of C++ STL is present in the <type_traits> header file. The std::is_nothrow_copy_assignable template of C++ STL is used to check whether T is copy assignable type or not and this is known for not to throw any exception. It returns the boolean value either true or false.
Header File:
#include<type_traits>
Template Class:
template< class T > struct is_nothrow_copy_assignable;
Syntax:
std::is_nothrow_copy_assignable< datatype >::value << '\n'
Parameters: The template std::is_nothrow_copy_assignable accepts a single parameter T (Trait class) to check whether T is is_nothrow_copy_assignable type or not.
Return Value:
- True: If a given data type T is a nothrow copy assignable.
- False: If a given data type T is not a nothrow copy assignable.
Below is the program to demonstrate std::is_nothrow_copy_assignable in C++:
Program:
// C++ program to illustrate // std::is_nothrow_copy_assignable #include <bits/stdc++.h> #include <type_traits> using namespace std;
// Declare structures X and Y struct X {
}; struct Y {
Y& operator=( const Y&)
{
return * this ;
}
}; // Declare classes class A {
}; class B {
B() {}
}; class C : B {
}; class D {
virtual void fn() {}
}; // Driver Code int main()
{ cout << std::boolalpha;
// Check if int is is nothrow
// copy assignable or not
cout << "int: "
<< is_nothrow_copy_assignable< int >::value
<< endl;
// Check if struct X is nothrow
// copy assignable or not
cout << "struct X: "
<< is_nothrow_copy_assignable<X>::value
<< endl;
// Check if struct Y is isnothrow
// copy assignable or not
cout << "struct Y: "
<< is_nothrow_copy_assignable<Y>::value
<< endl;
// Check if int[2] is is nothrow
// copy assignable or not
cout << "int[2]: "
<< is_nothrow_copy_assignable< int [2]>::value
<< endl;
// Check if class A is a nothrow
// copy assignable or not
cout << "class A: "
<< is_nothrow_copy_assignable<A>::value
<< endl;
// Check if class B is a nothrow
// copy assignable or not
cout << "class B: "
<< is_nothrow_copy_assignable<B>::value
<< endl;
// Check if class C is a nothrow
// copy assignable or not
cout << "class C: "
<< is_nothrow_copy_assignable<C>::value
<< endl;
// Check if class D is a nothrow
// copy assignable or not
cout << "class D: "
<< is_nothrow_copy_assignable<D>::value
<< endl;
return 0;
} |
int: true struct X: true struct Y: false int[2]: false class A: true class B: true class C: true class D: true
Reference: http://www.cplusplus.com/reference/type_traits/is_nothrow_copy_assignable/