std::discard_block_engine::operator()
From cppreference.com
                    
                                        
                    < cpp | numeric | random | discard block engine
                    
                                                            
                    | result_type operator()(); | (since C++11) | |
Generates a random value. The state of the underlying engine is advanced one or more times.
Parameters
(none)
Return value
(none)
Exceptions
(none)
See also
| advances the adaptor's state by a specified amount (public member function) |