无法将多个初始化列表传递给可变函数模板 [英] Having trouble passing multiple initializer lists to variadic function template

问题描述

尝试传递可变数量的初始值列表时，我不明白错误消息：

I don't understand the error message when trying to pass a variable number of initializer lists:

template<typename... Values>
void foo(Values...)
{
}

int main()
{
    foo(1, 2, 3, "hello", 'a');   // OK

    foo({1}, {2, 3});             // ERROR
}

错误消息提示参数过多：

The error message complains about too many arguments:

prog.cpp: In function ‘int main()’:
prog.cpp:9:20: error: too many arguments to function
                      ‘void foo(Values ...) [with Values = {}]’
     foo({1}, {2, 3});
                    ^
prog.cpp:2:6: note: declared here
 void foo(Values...)
      ^

但是，我是否应该不能传递尽可能多的参数？ [ ideone link ]

However, should I not be able to pass as many arguments as I want? [ideone link]

推荐答案

问题很可能是推论。 {} 可以是任何参数的统一初始化。

The problem is likely deducibility. {} could be uniform initializers to any of the arguments.

这适用于：

#include <initializer_list>

template<typename... Values>
void foo(std::initializer_list<Values>... args)
{
}

template<typename... Values>
void foo(Values&&... args)
{
}

int main()
{    
    foo(1, 2, 3, "hello", 'a');
    foo({1}, {2, 3});
}

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