新しいgccで実装されていませんが、古いもので実装されていますか？

Question

コード：

#include <tuple> 
#include <cmath> 
#include <iostream> 

template <int N, typename Retrun_T, typename... Args_T> 
Retrun_T _TupleFunctionCall(Retrun_T (*function)(Args_T... Args), std::tuple<Args_T...> Args, Args_T... RealArgs) 
{ 
    return function(RealArgs...); 
} 

template <int N, typename Retrun_T, typename... Args_T, typename... Interm_Args_T> 
Retrun_T _TupleFunctionCall(Retrun_T (*function)(Args_T... Args), std::tuple<Args_T...> Args, Interm_Args_T... RealArgs) 
{ 
    return _TupleFunctionCall<N + 1>(function, Args, RealArgs..., std::get<N>(Args)); 
} 

template <typename Retrun_T, typename... Args_T> 
Retrun_T TupleFunctionCall(Retrun_T (*function)(Args_T... Args), std::tuple<Args_T...> Args) 
{ 
    return _TupleFunctionCall<1>(function, Args, std::get<0>(Args)); 
} 

int main(int argc, char *argv[]) 
{ 
    std::cout << TupleFunctionCall<double, double, double>(&std::pow, std::tuple<double, double>(10, 2)) << std::endl; 
} 

コンパイルとg ++ 4.4.2で細かい動作しますが、G ++ 4.5.2でエラーが発生します。

prog.cpp: In function 'Retrun_T _TupleFunctionCall(Retrun_T (*)(Args_T ...), std::tuple<_Tail ...>, Interm_Args_T ...) [with int N = 1, Retrun_T = double, Args_T = {double, double}, Interm_Args_T = {double}]':
prog.cpp:20:67: instantiated from 'Retrun_T TupleFunctionCall(Retrun_T (*)(Args_T ...), std::tuple<_Elements ...>) [with Retrun_T = double, Args_T = {double, double}]'
prog.cpp:25:104: instantiated from here
prog.cpp:14:84: sorry, unimplemented: use of 'type_pack_expansion' in template
prog.cpp:14:84: error: call of overloaded '_TupleFunctionCall(double (*&)(double, double), std::tuple&, double&, double&)' is ambiguous prog.cpp:6:10: note: candidates are: Retrun_T _TupleFunctionCall(Retrun_T (*)(Args_T ...), std::tuple<_Tail ...>, Args_T ...) [with int N = 2, Retrun_T = double, Args_T = {double, double}]
prog.cpp:12:10: note: Retrun_T _TupleFunctionCall(Retrun_T (*)(Args_T ...), std::tuple<_Tail ...>, Interm_Args_T ...) [with int N = 2, Retrun_T = double, Args_T = {double, double}, Interm_Args_T = {double, double}]

なぜそれが古いグラムで++ではなく、新たなに実装されています1？

Answer 1

質問は可変長引数テンプレートに関連すると思われる、あなたは、リンクを参照してください可能性があります。これはG ++の一生の間に何度か来ているようGCC error with variadic templates: "Sorry, unimplemented: cannot expand 'Identifier...' into a fixed-length argument list"