# `nullptr`, the pointer literal (since C++11)

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### Syntax

`nullptr` |  |

### Explanation

The keyword `nullptr` denotes the pointer literal. It is a prvalue of type std::nullptr_t. There exist implicit conversions from `nullptr` to null pointer value of any pointer type and any pointer to member type. Similar conversions exist for any null pointer constant, which includes values of type std::nullptr_t as well as the macro NULL.

### Keywords

`nullptr`

### Example

Demonstrates that `nullptr` retains the meaning of null pointer constant even if it is no longer a literal.

Run this code

    #include <cstddef>
    #include <iostream>

    template<class T>
    constexpr T clone(const T& t)
    {
        return t;
    }

    void g(int*)
    {
        std::cout << "Function g called\n";
    }

    int main()
    {
        g(nullptr);        // Fine
        g(NULL);           // Fine
        g(0);              // Fine

        g(clone(nullptr)); // Fine
    //  g(clone(NULL));    // ERROR: non-literal zero cannot be a null pointer constant
    //  g(clone(0));       // ERROR: non-literal zero cannot be a null pointer constant
    }

Output:

    Function g called
    Function g called
    Function g called
    Function g called

### References

- C++23 standard (ISO/IEC 14882:2024):

  - 7.3.12 Pointer conversions [conv.ptr]

- C++20 standard (ISO/IEC 14882:2020):

  - 7.3.12 Pointer conversions [conv.ptr]

- C++17 standard (ISO/IEC 14882:2017):

  - 7.11 Pointer conversions [conv.ptr]

- C++14 standard (ISO/IEC 14882:2014):

  - 4.10 Pointer conversions [conv.ptr]

- C++11 standard (ISO/IEC 14882:2011):

  - 4.10 Pointer conversions [conv.ptr]

### See also

NULL | implementation-defined null pointer constant (macro constant)
nullptr_t (C++11) | the type of the null pointer literal `nullptr` (typedef)
C documentation for nullptr

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