Namespaces
Variants

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

    From cppreference.com
     
    C++
     
    Memory management library
    (exposition only*)
    Allocators
    Uninitialized memory algorithms
    Constrained uninitialized memory algorithms
    Memory resources
    Uninitialized storage (until C++20)
    (until C++20*)
    (until C++20*)
    (until C++20*)

    Garbage collector support (until C++23)
    (C++11)(until C++23)
    (C++11)(until C++23)
    (C++11)(until C++23)
    (C++11)(until C++23)
    (C++11)(until C++23)
    (C++11)(until C++23)
    Low level memory
    management
        
    (C++11)
    (C++11)
    (C++17)
    (C++20)
    (C++17)
    Smart pointers
    (C++11)
    (C++11)
    (C++11)
    (until C++17*)
    (C++11)
    (C++17)
    (C++26)
    (C++26)
    (C++11)
    (C++11)
    (C++11)
    (C++23)
    (C++23)
    Miscellaneous
    (C++11)
    (C++20)
    (C++11)
    (C++11)
    (C++20)
    (C++26)
    C Library
    (C++26)
    (C++26)
    (C++26)
     
    std::pmr::polymorphic_allocator
     
    Defined in header <memory_resource> 
    template< class T1, class T2 >
bool operator==( const std::pmr::polymorphic_allocator<T1>& lhs,
                 const std::pmr::polymorphic_allocator<T2>& rhs ) noexcept;
    		(1) (since C++17) 
    friend bool operator==( const polymorphic_allocator& lhs,
                        const polymorphic_allocator& rhs ) noexcept;
    		(2) (since C++17) 
    template< class T1, class T2 >
bool operator!=( const std::pmr::polymorphic_allocator<T1>& lhs,
                 const std::pmr::polymorphic_allocator<T2>& rhs ) noexcept;
    		(3) (since C++17)
    (until C++20) 
    friend bool operator!=( const polymorphic_allocator& lhs,
                        const polymorphic_allocator& rhs ) noexcept;
    		(4) (since C++17)
    (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 with types convertible to it overload added