Can parameter pack function arguments be defaulted?

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0

This is a point about which gcc 4.9.2 and clang 3.5.2 are in sharp disgreement. The program:

template<typename ...Ts>
int foo(int i = 0, Ts &&... args)
{
    return i + sizeof...(Ts);
}

int main()
{
    return foo();
}

compiles without comment from gcc (-std=c++11 -Wall -pedantic). Clang says:

error: missing default argument on parameter 'args'

With foo amended to:

template<typename ...Ts>
int foo(int i = 0, Ts &&... args = 0)
{
    return i + sizeof...(Ts);
}

clang has no complaints, but gcc says:

error: parameter pack ‘args’ cannot have a default argument

Which compiler is right?

asked 1 min ago

Mike Kinghan

6,320

Can parameter pack function arguments be defaulted?