c++ - Avoid the most vexing parse

Question

How do I get the compiler to create temporaries, use the default constructor on them while not defining a function?

struct B {};
template<class T> struct C {};

template<class T,class T1>
struct A
{
  A(const T& t,const T1& t1): m_t(t),m_t1(t1)
  {
    std::cout << __PRETTY_FUNCTION__ << "
";
  }

  T m_t;
  T1 m_t1;
};


int main() {
  A< B , C<B> > a0( B() , C<B>() );   // Function definition
  A< B , C<B> > a1( B b , C<B> c );   // dito, *at least A(const T& t,const T1& t1) not called
}

Answer 1

You can wrap one of your arguments in an extra set of parentheses to stop it from being parsed as a function declaration:

A< B , C<B> > a0( (B()) , C<B>() );

Or even better, if you have access to a C++11 compiler, use brace initialization:

A< B , C<B> > a0{ B() , C<B>() };