This function only participates in overload resolution if is_error_condition_enum<ErrorConditionEnum>::value is true. Which is the case when errc is used as the ErrorConditionEnum type.
Member function assign can be used to assign a new value to the error_condition object using an integer value and a category, instead of an enum value.
Parameters
e
Error condition enum value of an enum type for which is_error_condition_enum has a value member with a value of true.
If this is a value of type errc, the object is set to the appropriate error condition value of the generic_category.