NAME

std::pmr::operator==,std::pmr::operator!= - std::pmr::operator==,std::pmr::operator!=

Synopsis

Defined in header <memory_resource>
template< class T1, class T2 >

bool operator==( const std::pmr::polymorphic_allocator<T1>& lhs, (1) (since C++17)

const std::pmr::polymorphic_allocator<T2>& rhs ) noexcept;
friend bool operator==( const polymorphic_allocator& lhs, (2) (since C++17)
const polymorphic_allocator& rhs ) noexcept;
template< class T1, class T2 >
(since C++17)
bool operator!=( const std::pmr::polymorphic_allocator<T1>& lhs, (3) (until C++20)

const std::pmr::polymorphic_allocator<T2>& rhs ) noexcept;
friend bool operator!=( const polymorphic_allocator& lhs, (4) (since C++17)
const polymorphic_allocator& rhs ) noexcept; (until C++20)

Compares two polymorphic allocators. Two polymorphic allocators compare equal if
their underlying memory resource compares equal.

1) Returns *lhs.resource() == *rhs.resource()
2) Same as (1), allowing conversion to polymorphic_allocator.
This function is not visible to ordinary unqualified or qualified lookup, and can
only be found by argument-dependent lookup when std::pmr::polymorphic_allocator is
an associated class of the arguments.
3) Returns !(lhs == rhs)
4) Same as (3), allowing conversion to polymorphic_allocator.
This function is not visible to ordinary unqualified or qualified lookup, and can
only be found by argument-dependent lookup when std::pmr::polymorphic_allocator is
an associated class of the arguments.

The != operator is synthesized from operator==. (since C++20)

Parameters

lhs, rhs - polymorphic allocators to compare

Return value

1-2) *lhs.resource() == *rhs.resource()
3-4) !(lhs == rhs)

Defect reports

The following behavior-changing defect reports were applied retroactively to
previously published C++ standards.

DR Applied to Behavior as published Correct behavior
LWG 3683 C++17 polymorphic_allocator could not be compared overload added
with types convertible to it