std::logical_not - cppreference.com (original) (raw)
| Defined in header | | | | -------------------------------------------------------------------------------------- | | ------------- | | 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 parameter and return types (class template specialization) [edit] | (since C++14) |
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[edit] Member types
| Type | Definition |
|---|---|
| result_type (deprecated in C++17)(removed in C++20) | bool |
| argument_type (deprecated in C++17)(removed in C++20) | T |
| These member types are obtained via publicly inheriting std::unary_function<T, bool>. | (until C++11) |
|---|
[edit] Member functions
| | returns the logical NOT of the argument (public member function) | | ------------------------------------------------------------------- |
std::logical_not::operator()
| bool operator()( const T& arg ) const; | | (constexpr since C++14) | | -------------------------------------- | | ----------------------- |
Returns the logical NOT of arg.
Parameters
| arg | - | value to compute logical NOT of |
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Return value
The result of !arg.
[edit] Exceptions
May throw implementation-defined exceptions.
Possible implementation
constexpr // since C++14 bool operator()(const T& arg) const { return !arg; }