bind(&X::f, args) +bind(&X::f, args)is equivalent to
-bind<R>(mem_fn(&X::f), args) +bind<R>(mem_fn(&X::f), args)-where R is the return type of X::f (for member functions) or a - const reference to the type of the member (for data members.) +
where R is the return type of X::f (for member functions) or the + type of the member (for data members.)
[Note: mem_fn creates function objects that are able to accept a pointer, a reference, or a smart pointer to an object as its first argument; for @@ -220,8 +220,8 @@ int i = 5; bind(&X::f, ref(x), _1)(i); // x.f(i) bind(&X::f, &x, _1)(i); //(&x)->f(i) -bind(&X::f, x, _1)(i); // (internal copy of x).f(i) -bind(&X::f, p, _1)(i); // (internal copy of p)->f(i) +bind(&X::f, x, _1)(i); // (internal copy of x).f(i) +bind(&X::f, p, _1)(i); // (internal copy of p)->f(i)
The last two examples are interesting in that they produce "self-contained" function objects. bind(&X::f, x, _1) stores a copy of x. bind(&X::f, @@ -436,7 +436,7 @@ int main() int main() { boost::bind(&X::f, 1); // error, X::f takes two arguments - boost::bind(&X::f, _1, 1); // OK + boost::bind(&X::f, _1, 1); // OK }
All function objects returned by mem_fn expose a result_type typedef that represents the return type of the member function. For data members, result_type - is defined as a const reference to the type of the member. + is defined as the type of the member.