std::is_error_code_enum

 

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std::error_code

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error_code::error_code

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operator<<

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is_error_code_enum

hash<std::error_code>

 

Defined in header <system_error>
template< class T > struct is_error_code_enum;		(since C++11)

If T is an error code enumeration (such as std::io_errc and std::future_errc), this template provides the member constant value equal true. For any other type, value is false.

This template may be specialized for a program-defined type to indicate that the type is eligible for std::error_code implicit conversion.

Helper variable template

template< class T > constexpr bool is_error_code_enum_v = is_error_code_enum<T>::value;		(since C++17)

Inherited from std::integral_constant

Member constants

value [static]

true if T is an error code enum, false otherwise (public static member constant)

Member functions

operator bool	converts the object to bool, returns value (public member function)
operator() (C++14)	returns value (public member function)

Member types

Type	Definition
value_type	bool
type	std::integral_constant<bool, value>

Run this code

#include <ios>
#include <system_error>
 
static_assert(std::is_error_code_enum_v<decltype(std::io_errc::stream)>);
static_assert(!std::is_error_code_enum_v<std::error_category>);
 
int main() {}

See also

is_error_condition_enum (C++11)

identifies an enumeration as an std::error_condition (class template)