std::chrono::duration_values
From cppreference.com
                    
                                        
                    
                    
                                                            
                    |   Defined in header  
<chrono>
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|   template <class Rep> 
struct duration_values;  | 
(since C++11) | |
The std::chrono::duration_values type defines three common durations:
- std::chrono::duration_values::zero
 - std::chrono::duration_values::min
 - std::chrono::duration_values::max
 
The zero, min, and max methods in std::chrono::duration forward their work to these methods.
This type can be specialized if the representation Rep requires a specific implementation to return these duration objects.
[edit] Member functions
|    [static] 
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   returns a zero-length representation  (public static member function)  | 
|    [static] 
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   returns the smallest possible representation  (public static member function)  | 
|    [static] 
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   returns the largest possible representation  (public static member function)  |