what do the (...) arguments in C++ do

Question

I'll get to the point, in thread.h the constructor to a thread is defined with what is below.

template<class _Fn,
    class... _Args>
    explicit thread(_Fn&& _Fx, _Args&&... _Ax)
    {   // construct with _Fx(_Ax...)
    _Launch(&_Thr,
         _STD bind(_Decay_copy(_STD forward<_Fn>(_Fx)),
            _Decay_copy(_STD forward<_Args>(_Ax))...));
    }

I was wondering what the ... does I've tried googling and looking on stackoverflow but the answer doesn't seem to anywhere! Thank you in advance :)

possible duplicate of [Variadic templates](http://stackoverflow.com/questions/276188/variadic-templates) — songyuanyao, Jun 24 '14 at 05:43

score 4 · Accepted Answer · answered Jun 24 '14 at 05:40

4

This is a C++11 construct, called variadic templates (follow the links)

answered Jun 24 '14 at 05:40

Basile Starynkevitch

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score 2 · Answer 2 · answered Jun 24 '14 at 05:45

2

Its called variadic template. It allows you to write templates with variable number of arguments. As far as I can tell here it allows you to define thread running function returning _Fn type with _Args arguments list by partial binding.

answered Jun 24 '14 at 05:45

Mateusz Kubuszok

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Basically allowing you to pass a number of arguments to a a function pointer. – Joshua Waring Jun 24 '14 at 06:08

what do the (...) arguments in C++ do

2 Answers2