What is a Bool <true> in C ++ - is it from a boost?

Question

I am trying to use some sample code and my compiler will not compile this line:

static void exitActions(Host& h, Bool<true>) {}

The compiler is MS VS2005. I do not recognize Bool, so I do not know how to replace it. Is this default equivalent:

static void exitActions(Host& h, bool b = true) {}

Sample is from http://accu.org/index.php/journals/252 . The code is just fragments of text - there are no fragments about what # include'd is - it's so hard to work. There is no definition for the Bool template.

Answer 1

I think Booldefined as

template <bool B> struct Bool{};

You can use this for some basic pattern matching:

void exitActions(Bool<true>)  { std::cout << "called with true\n"; }
void exitActions(Bool<false>) { std::cout << "called with false\n"; }

int main()
{
  exitActions(Bool<true>());  // prints "called with true"
  exitActions(Bool<false>()); // prints "called with false"
}

, , , Bool<true> Bool<false>. http://accu.org/index.php/journals/252 ( ) .

Tran<T,S,T>::entryActions(host_, Bool<false>());