| 1 | // Boost enable_if library |
|---|---|
| 2 | |
| 3 | // Copyright 2003 (c) The Trustees of Indiana University. |
| 4 | |
| 5 | // Use, modification, and distribution is subject to the Boost Software |
| 6 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at |
| 7 | // http://www.boost.org/LICENSE_1_0.txt) |
| 8 | |
| 9 | // Authors: Jaakko Jarvi (jajarvi at osl.iu.edu) |
| 10 | // Jeremiah Willcock (jewillco at osl.iu.edu) |
| 11 | // Andrew Lumsdaine (lums at osl.iu.edu) |
| 12 | |
| 13 | #include <boost/config.hpp> |
| 14 | #include <boost/utility/enable_if.hpp> |
| 15 | #include <boost/type_traits/is_arithmetic.hpp> |
| 16 | #include <boost/core/lightweight_test.hpp> |
| 17 | |
| 18 | using boost::enable_if; |
| 19 | using boost::is_arithmetic; |
| 20 | |
| 21 | template<class T> struct not_ |
| 22 | { |
| 23 | BOOST_STATIC_CONSTANT( bool, value = !T::value ); |
| 24 | }; |
| 25 | |
| 26 | namespace A { |
| 27 | template<class T> |
| 28 | typename enable_if<is_arithmetic<T>, bool>::type |
| 29 | arithmetic_object(T /*t*/) { return true; } |
| 30 | } |
| 31 | |
| 32 | namespace B { |
| 33 | template<class T> |
| 34 | typename enable_if<not_<is_arithmetic<T> >, bool>::type |
| 35 | arithmetic_object(T /*t*/) { return false; } |
| 36 | } |
| 37 | |
| 38 | int main() |
| 39 | { |
| 40 | using namespace A; |
| 41 | using namespace B; |
| 42 | BOOST_TEST(arithmetic_object(1)); |
| 43 | BOOST_TEST(arithmetic_object(1.0)); |
| 44 | |
| 45 | BOOST_TEST(!arithmetic_object("1")); |
| 46 | BOOST_TEST(!arithmetic_object(static_cast<void*>(0))); |
| 47 | |
| 48 | return boost::report_errors(); |
| 49 | } |
| 50 |