Defined in header <functional>
template< class T = void >
struct bit_not;
(since C++14)

Function object for performing bitwise NOT. Effectively calls operator~ on type T.


The standard library provides a specialization of std::bit_not when T is not specified, which leaves the parameter types and return type to be deduced.

function object implementing ~x deducing argument and return types
(class template specialization)

Member types

Type Definition
result_type (deprecated in C++17)(removed in C++20) T
argument_type (deprecated in C++17)(removed in C++20) T

Member functions

returns the result of bitwise NOT of its argument
(public member function)


constexpr T operator()( const T& arg ) const;
(since C++14)

Returns the result of bitwise NOT of arg.


arg - value to compute bitwise NOT of

Return value

The result of ~arg.


May throw implementation-defined exceptions.

Possible implementation

constexpr T operator()(const T& arg) const
    return ~arg;


Although std::bit_not is added via post-C++11 proposal N3421, it is treated as a part of the resolution for LWG issue 660 (except for its transparent specialization std::bit_not<>) by common implementations, and thus available in their C++98/03 mode.

© cppreference.com
Licensed under the Creative Commons Attribution-ShareAlike Unported License v3.0.