Namespaces
Variants
Views
Actions

std::logical_not

From cppreference.com
< cpp‎ | utility‎ | functional
 
 
 
Function objects
Function wrappers
(C++11)
(C++11)
(C++17)
Bind
(C++11)
Reference wrappers
(C++11)(C++11)
Operator wrappers
Negators
Deprecated binders and adaptors
(until C++17)
(until C++17)
(until C++17)
(until C++17)
(until C++17)(until C++17)(until C++17)(until C++17)
(until C++17)
(until C++17)(until C++17)(until C++17)(until C++17)
(until C++17)(until C++17)
(until C++17)(until C++17)
 
Defined in header <functional>
template< class T >
struct logical_not;
(until C++14)
template< class T = void >
struct logical_not;
(since C++14)

Function object for performing logical NOT (logical negation). Effectively calls operator! for type T.

Contents

[edit] Specializations

The standard library provides a specialization of std::logical_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) [edit]
(since C++14)

[edit] Member types

Type Definition
result_type bool
argument_type T

[edit] Member functions

operator()
returns the logical NOT of the argument
(public member function)

std::logical_not::operator()

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

Returns the logical NOT of arg.

Parameters

arg - value to compute logical NOT of

Return value

The result of !arg.

Exceptions

(none)

Possible implementation

const bool operator()(const T &arg) const 
{
    return !arg;
}