// Boost
FOLLY_ASSUME_FBVECTOR_COMPATIBLE_1(boost::shared_ptr);
+#define FOLLY_CREATE_HAS_MEMBER_TYPE_TRAITS(classname, type_name) \
+ template <typename T> \
+ struct classname { \
+ template <typename C> \
+ constexpr static bool test(typename C::type_name*) { return true; } \
+ template <typename> \
+ constexpr static bool test(...) { return false; } \
+ constexpr static bool value = test<T>(nullptr); \
+ }
+
#define FOLLY_CREATE_HAS_MEMBER_FN_TRAITS_IMPL(classname, func_name, cv_qual) \
template <typename TTheClass_, typename RTheReturn_, typename... TTheArgs_> \
class classname<TTheClass_, RTheReturn_(TTheArgs_...) cv_qual> { \
EXPECT_FALSE((folly::greater_than<uint8_t, 255u, uint8_t>(254u)));
}
+struct membership_no {};
+struct membership_yes { using x = void; };
+FOLLY_CREATE_HAS_MEMBER_TYPE_TRAITS(has_member_type_x, x);
+
+TEST(Traits, has_member_type) {
+ EXPECT_FALSE(bool(has_member_type_x<membership_no>::value));
+ EXPECT_TRUE(bool(has_member_type_x<membership_yes>::value));
+}
+
int main(int argc, char ** argv) {
testing::InitGoogleTest(&argc, argv);
gflags::ParseCommandLineFlags(&argc, &argv, true);