Viewing file:  sfinae5.C (964 B) -rw-r--r--
Select action/file-type:
 (+) |  (+) |  (+) | Code (+) | Session (+) |  (+) | SDB (+) |  (+) |  (+) |  (+) |  (+) |  (+) |
// DR 339
//
// Test of the use of member functions with SFINAE
typedef char yes_type;
struct no_type { char data[2]; };
template<typename T> T create_a();
template<bool, typename T = void> struct enable_if { typedef T type; };
template<typename T> struct enable_if<false, T> { };
template<typename T>
typename enable_if<(sizeof(create_a<T>().foo(), 1) > 0),
yes_type>::type
check_has_member_foo(const volatile T&);
no_type check_has_member_foo(...);
template<typename T>
struct has_foo
{
static const bool value =
(sizeof(check_has_member_foo(create_a<T const&>())) == sizeof(yes_type));
};
struct X { };
struct Y {
void foo();
};
struct Z {
void foo(int);
};
struct A {
int foo;
};
struct B {
static int foo();
};
int a1[has_foo<X>::value? -1 : 1];
int a2[has_foo<Y>::value? 1 : -1];
int a3[has_foo<Z>::value? -1 : 1];
int a4[has_foo<int>::value? -1 : 1];
int a5[has_foo<A>::value? -1 : 1];
int a6[has_foo<B>::value? 1 : -1];
|
