NAME¶

std::map::value_compare - std::map::value_compare

Synopsis¶

class value_compare;

std::map::value_compare is a function object that compares objects of type
std::map::value_type (key-value pairs) by comparing of the first components of the
pairs.

Member types¶

Type Definition
result_type (deprecated in C++17)(removed in C++20) bool
first_argument_type (deprecated in C++17)(removed in C++20) value_type
second_argument_type (deprecated in C++17)(removed in C++20) value_type

These member types are obtained via publicly inheriting (until C++11)
std::binary_function<value_type, value_type, bool>.

Protected member objects¶

Compare comp the stored comparator
(protected member object)

Member functions¶

constructor constructs a new value_compare object
(protected member function)
operator() compares two values of type value_type
(public member function)

std::map<Key,T,Compare,Alloc>::value_compare::value_compare

protected:
value_compare( Compare c );

Initializes the internal instance of the comparator to c.

Parameters¶

c - comparator to assign

std::map<Key,T,Compare,Alloc>::value_compare::operator()

bool operator()( const value_type& lhs, const value_type& rhs ) const;

Compares lhs.first and rhs.first by calling the stored comparator.

Parameters¶

lhs, rhs - values to compare

Return value¶

comp(lhs.first, rhs.first).

Exceptions¶

May throw implementation-defined exceptions.