1 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s 2 3 // Metafunction to extract the Nth type from a set of types. 4 template<unsigned N, typename ...Types> struct get_nth_type; 5 6 template<unsigned N, typename Head, typename ...Tail> 7 struct get_nth_type<N, Head, Tail...> : get_nth_type<N-1, Tail...> { }; 8 9 template<typename Head, typename ...Tail> 10 struct get_nth_type<0, Head, Tail...> { 11 typedef Head type; 12 }; 13 14 // Placeholder type when get_nth_type fails. 15 struct no_type {}; 16 17 template<unsigned N> 18 struct get_nth_type<N> { 19 typedef no_type type; 20 }; 21 22 template<typename ...Args> 23 typename get_nth_type<0, Args...>::type first_arg(Args...); 24 25 template<typename ...Args> 26 typename get_nth_type<1, Args...>::type second_arg(Args...); 27 28 // Test explicit specification of function template arguments. 29 void test_explicit_spec_simple() { 30 int *ip1 = first_arg<int *>(0); 31 int *ip2 = first_arg<int *, float*>(0, 0); 32 float *fp1 = first_arg<float *, double*, int*>(0, 0, 0); 33 } 34 35 // Template argument deduction can extend the sequence of template 36 // arguments corresponding to a template parameter pack, even when the 37 // sequence contains explicitly specified template arguments. 38 void test_explicit_spec_extension(double *dp) { 39 int *ip1 = first_arg<int *>(0, 0); 40 int *ip2 = first_arg<int *, float*>(0, 0, 0, 0); 41 float *fp1 = first_arg<float *, double*, int*>(0, 0, 0); 42 int *i1 = second_arg<float *>(0, (int*)0, 0); 43 double *dp1 = first_arg<>(dp); 44 } 45 46 template<typename ...Types> 47 struct tuple { }; 48 49 template<typename ...Types> 50 void accept_tuple(tuple<Types...>); 51 52 void test_explicit_spec_extension_targs(tuple<int, float, double> t3) { 53 accept_tuple(t3); 54 accept_tuple<int, float, double>(t3); 55 accept_tuple<int>(t3); 56 accept_tuple<int, float>(t3); 57 } 58 59 template<typename R, typename ...ParmTypes> 60 void accept_function_ptr(R(*)(ParmTypes...)); 61 62 void test_explicit_spec_extension_funcparms(int (*f3)(int, float, double)) { 63 accept_function_ptr(f3); 64 accept_function_ptr<int>(f3); 65 accept_function_ptr<int, int>(f3); 66 accept_function_ptr<int, int, float>(f3); 67 accept_function_ptr<int, int, float, double>(f3); 68 } 69
