libs/utility/identity_type/test/template.cpp
// Copyright (C) 2009-2012 Lorenzo Caminiti
// Distributed under the Boost Software License, Version 1.0
// (see accompanying file LICENSE_1_0.txt or a copy at
// http://www.boost.org/LICENSE_1_0.txt)
// Home at http://www.boost.org/libs/utility/identity_type
#include <boost/utility/identity_type.hpp>
#include <map>
#include <iostream>
//[template_f_decl
#define ARG(type, n) type arg ## n
template<typename T>
void f( // Prefix macro with `typename` in templates.
ARG(typename BOOST_IDENTITY_TYPE((std::map<int, T>)), 1)
) {
std::cout << arg1[0] << std::endl;
}
//]
//[template_g_decl
template<typename T>
void g(
std::map<int, T> arg1
) {
std::cout << arg1[0] << std::endl;
}
//]
int main() {
//[template_f_call
std::map<int, char> a;
a[0] = 'a';
f<char>(a); // OK...
// f(a); // ... but error.
//]
//[template_g_call
g<char>(a); // OK...
g(a); // ... and also OK.
//]
return 0;
}