std::experimental::pmr::monotonic_buffer_resource::upstream_resource
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                    < cpp | experimental | monotonic buffer resource
                    
                                                            
                    | memory_resource* upstream_resource() const; | (library fundamentals TS) | |
Returns a pointer to the upstream memory resource. This is the same value as the upstream argument passed to the constructor of this object.
See also
| Constructs a monotonic_buffer_resource(public member function) |