http://gcc.gnu.org/bugzilla/show_bug.cgi?id=54468
Bug #: 54468
Summary: type trait is_unsigned<...>::value for C++11 enum
class with underlying unsigned type not true
Classification: Unclassified
Product: gcc
Version: 4.7.0
Status: UNCONFIRMED
Severity: normal
Priority: P3
Component: libstdc++
AssignedTo: [email protected]
ReportedBy: [email protected]
The is_unsigned<> type trait is not detecting the underlying signedness of a
C++11 enum class or enum.
The output of:
#include <iostream>
#include <type_traits>
using namespace std;
int main()
{
enum class enum_class_type: unsigned char
{
ENUM_CLASS_VALUE0,
ENUM_CLASS_VALUE1
};
cout << boolalpha << "is_enum<enum_class_type>::value = " <<
is_enum<enum_class_type>::value << endl;
cout << "is_unsigned<enum_class_type>::value = " <<
is_unsigned<enum_class_type>::value << endl;
enum enum_type: unsigned char
{
ENUM_VALUE0,
ENUM_VALUE1
};
cout << boolalpha << "is_enum<enum_type>::value = " <<
is_enum<enum_type>::value << endl;
cout << "is_unsigned<enum_type>::value = " << is_unsigned<enum_type>::value
<< endl;
}
should be:
is_enum<enum_class_type>::value = true
is_unsigned<enum_class_type>::value = true
is_enum<enum_type>::value = true
is_unsigned<enum_type>::value = true
but is:
is_enum<enum_class_type>::value = true
is_unsigned<enum_class_type>::value = false
is_enum<enum_type>::value = true
is_unsigned<enum_type>::value = false
