Stdis Destructible In C++

In this article, we will discuss the std::is_destructable in C++ with its syntax and examples.

What is the std::is_destructible?

In C++, a type trait known as std::isdestructible function. It helps to determine if a certain type can be destroyed with a delete operator. It is defined in <typetraits> header and it is also a part of the C++11 standard. This feature is especially helpful in template metaprogramming when decisions about types must be made at compilation time.

The std::is_destructible trait can be used to determine whether an object of a particular type can be destroyed without resulting in a compile-time error. Whether or not the type has a publicly accessible destructor is indicated by the boolean value (true or false) that is returned.

The Header File is stated as,

#include<type_traits>

Syntax:

It has the following syntax:

template <class T>
struct is_destructible;

Return Value:

If the type T is void, a public destructor, or is a reference type, the std::is_destructible value member constant is true. Otherwise, it returns false value.

Pseudocode:

function isDestructible(Type):
    try:
        // Attempt to create a temporary instance of Type and immediately destroy it
        temp = new Type()
        destroy(temp)
        return true
    catch DestructionError:
        // If an error occurs during destruction, the type is not destructible
        return false

function destroy(obj):
    // Perform destruction logic for obj
    // For example, call the destructor explicitly
    call obj.~Type()

// Example usage
print "Is int destructible? ", isDestructible(int)
print "Is class with destructor destructible?", isDestructible(ClassWithDestructor)
print "Is class without destructor destructible? ", isDestructible(ClassWithoutDestructor)

Example:

Let us take an example to illustrate the std::is_destructible in C++.

#include<iostream>
#include <type_traits>
// A class with a public destructor
class A {
public:
    ~A() {}
};

// A class with a private destructor
class B {
private:
    ~B() {}
};

// A function template that checks if a type is destructible
template <typename T>
void check_destructible() {
std::cout<<"Type" << typeid(T).name()<<"is destructible:" << std::is_destructible<T>:: value<<std::endl;
}
int main() {
    check_destructible<A>(); // Output: Type 1A is destructible: true
    check_destructible<B>(); // Output: Type 1B is destructible: false
    check_destructible<int>(); // Output: Type i is destructible: true
    return 0;
}

Output:

Use Cases:

There are several use cases of std::is_destructible in C++. Some use cases are as follows:

• ✅ Depending on whether a type is destructible or not, std::is_destructible can be used in template metaprogramming to activate or disable specific capabilities.
• ✅ Function overloads and template specializations can be conditionally enabled or disabled in SFINAE (Substitution Failure Is Not An Error).

Limitations:

There are several limitations of std::is_destructible in C++. Some use cases are as follows:

• ✅ The std:: is_destructible ignores the destructor's virtuality. It is verify whether the type has an accessible destructor.
• ✅ It may not work as expected types with deleted or inaccessible destructors.

Similar Traits of Type:

• ✅ std::istriviallydestructible: It will determine whether the destructor of a type is trivial or not.
• ✅ std::isnothrowdestructible: It will verify whether the destructor is capable of throwing expections.