std::is_error_code_enum<std::io_errc>
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                    | Defined in header  <ios> | ||
| template< > struct is_error_code_enum<std::io_errc> : public std::true_type { }; | (since C++11) | |
This specialization of std::is_error_code_enum informs other library components that values of type std::io_errc are enumerations that hold error codes, which makes them implicitly convertible and assignable to objects of type std::error_code.
| Contents | 
Inherited from std::integral_constant
Member constants
| value [static] | true (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> | 
[edit] Example
The comparison between e.code() and std::io_errc::stream compiles because std::is_error_code_enum<std::io_errc>::value == true
Run this code
#include <iostream> #include <fstream> int main() { std::ifstream f("doesn't exist"); try { f.exceptions(f.failbit); } catch (const std::ios_base::failure& e) { std::cout << "Caught an ios_base::failure.\n"; if(e.code() == std::io_errc::stream) std::cout << "The error code is std::io_errc::stream\n"; } }
Output:
Caught an ios_base::failure. The error code is std::io_errc::stream
[edit] See also
| (C++11) | identifies a class as an error_code enumeration (class template) | 
| (C++11) | holds a platform-dependent error code (class) | 
| (C++11) | the IO stream error codes (enum) | 


