std::is_error_condition_enum
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                    < cpp | error | error condition
                    
                                                            
                    | Defined in header  <system_error> | ||
| template< class T > struct is_error_condition_enum; | (since C++11) | |
If T is an error condition enum, this template provides the member constant value equal true.  For any other type, value is false.
This template may be specialized for a user-defined type to indicate that the type is eligible for std::error_code and std::error_condition automatic conversions.
The following class of the standard library is an error condition enum: std::errc.
| Contents | 
Inherited from std::integral_constant
Member constants
| value [static] | true if Tis an error condition enum, false otherwise(public static member constant) | 
Member functions
| operator bool | converts the object to bool, returns value(public member function) | 
Member types
| Type | Definition | 
| value_type | bool | 
| type | std::integral_constant<bool, value> | 


