std::experimental::pmr::polymorphic_allocator::polymorphic_allocator
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                    < cpp | experimental | polymorphic allocator
                    
                                                            
                    | polymorphic_allocator(); | (1) | |
| polymorphic_allocator( const polymorphic_allocator& other ) = default; | (2) | |
| template< class U >  polymorphic_allocator( const polymorphic_allocator<U>& other ); | (3) | |
| polymorphic_allocator( memory_resource* r); | (4) | |
Constructs a new polymorphic_allocator.
1) Constructs a 
polymorphic_allocator using the return value of std::experimental::pmr::get_default_resource() as the underlying memory resource.2-3) Constructs a 
polymorphic_allocator using other.resource() as the underlying memory resource.4) Constructs a 
polymorphic_allocator using r as the underlying memory resource. This constructor provides an implicit conversion from memory_resource*.[edit] Parameters
| other | - | another polymorphic_allocatorto copy from | 
| r | - | pointer to the memory resource to use. May not be null. | 
[edit] Exceptions
1,3) 
noexcept specification:  
noexcept
  4) Throws nothing.


