1 // RUN: %clang_cc1 -std=c++11 -fsyntax-only -verify %s 2 // expected-no-diagnostics 3 4 // Metafunction to extract the Nth type from a set of types. 5 template<unsigned N, typename ...Types> struct get_nth_type; 6 7 template<unsigned N, typename Head, typename ...Tail> 8 struct get_nth_type<N, Head, Tail...> : get_nth_type<N-1, Tail...> { }; 9 10 template<typename Head, typename ...Tail> 11 struct get_nth_type<0, Head, Tail...> { 12 typedef Head type; 13 }; 14 15 // Placeholder type when get_nth_type fails. 16 struct no_type {}; 17 18 template<unsigned N> 19 struct get_nth_type<N> { 20 typedef no_type type; 21 }; 22 23 template<typename ...Args> 24 typename get_nth_type<0, Args...>::type first_arg(Args...); 25 26 template<typename ...Args> 27 typename get_nth_type<1, Args...>::type second_arg(Args...); 28 29 // Test explicit specification of function template arguments. 30 void test_explicit_spec_simple() { 31 int *ip1 = first_arg<int *>(0); 32 int *ip2 = first_arg<int *, float*>(0, 0); 33 float *fp1 = first_arg<float *, double*, int*>(0, 0, 0); 34 } 35 36 // Template argument deduction can extend the sequence of template 37 // arguments corresponding to a template parameter pack, even when the 38 // sequence contains explicitly specified template arguments. 39 void test_explicit_spec_extension(double *dp) { 40 int *ip1 = first_arg<int *>(0, 0); 41 int *ip2 = first_arg<int *, float*>(0, 0, 0, 0); 42 float *fp1 = first_arg<float *, double*, int*>(0, 0, 0); 43 int *i1 = second_arg<float *>(0, (int*)0, 0); 44 double *dp1 = first_arg<>(dp); 45 } 46 47 template<typename ...Types> 48 struct tuple { }; 49 50 template<typename ...Types> 51 void accept_tuple(tuple<Types...>); 52 53 void test_explicit_spec_extension_targs(tuple<int, float, double> t3) { 54 accept_tuple(t3); 55 accept_tuple<int, float, double>(t3); 56 accept_tuple<int>(t3); 57 accept_tuple<int, float>(t3); 58 } 59 60 template<typename R, typename ...ParmTypes> 61 void accept_function_ptr(R(*)(ParmTypes...)); 62 63 void test_explicit_spec_extension_funcparms(int (*f3)(int, float, double)) { 64 accept_function_ptr(f3); 65 accept_function_ptr<int>(f3); 66 accept_function_ptr<int, int>(f3); 67 accept_function_ptr<int, int, float>(f3); 68 accept_function_ptr<int, int, float, double>(f3); 69 } 70
