std::pmr::unsynchronized_pool_resource::unsynchronized_pool_resource
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                    < cpp | memory | unsynchronized pool resource
                    
                                                            
                    |   unsynchronized_pool_resource();  | 
(1) | (since C++17) | 
|   explicit unsynchronized_pool_resource(std::pmr::memory_resource* upstream);  | 
(2) | (since C++17) | 
|   explicit unsynchronized_pool_resource(const std::pmr::pool_options& opts);  | 
(3) | (since C++17) | 
|   unsynchronized_pool_resource(const std::pmr::pool_options& opts, std::pmr::memory_resource* upstream);  | 
(4) | (since C++17) | 
|   unsynchronized_pool_resource(const unsynchronized_pool_resource&) = delete;  | 
(5) | (since C++17) | 
Constructs a unsynchronized_pool_resource.
1-4) Constructs a 
The overloads not taking
unsynchronized_pool_resource using the specified upstream memory resource and tuned according to the specified options. The resulting object holds a copy of upstream but does not own the resource to which upstream points.
The overloads not taking
opts as a parameter uses a default constructed instance of pool_options as the options. The overloads not taking upstream as a parameter uses the return value of std::pmr::get_default_resource() as the upstream memory resource.5) Copy constructor is deleted.
Parameters
| opts | - | a std::pmr::pool_options struct containing the constructor options | 
| upstream | - | the upstream memory resource to use | 
Exceptions
1-4) Throws only if a call to the 
allocate() function of the upstream resource throws. It is unspecified if or under what conditions such a call takes place.