Pass initializer_list to variadic template

[Peter87]

I'm trying to pass an initializer_list to a variadic template but it doesn't work.

#include <initializer_list>

template <class... Args>
void foo(std::initializer_list<double> values, Args... args)
{
}

int main()
{
	//error: too many arguments to function 'void foo(std::initializer_list<double, Args ...) [with Args = {}]>'
	foo({1, 2, 3}, {20, 30, 40});
}

If I change initializer_list to vector it generates the same kind of error so I guess it just don't like the {}-syntax. Is it not possible to do this?

[vlad from moscow]

I think that then the compiler sees {20, 30, 40} it can not deduce the type of the parameter.

[Cubbi]

The "{}-syntax" is not an expression, it cannot be used to deduce the type of a template parameter (with the special exceptions for auto and range-for loop).

Although GCC has (had?) a compiler extension where it deduces brace-enclosed lists as initializer_list, with a warning: "test.cc:11:29: warning: deducing ‘Args ...’ as ‘std::initializer_list<int>’ [enabled by default]"