ceph/src/boost/libs/core/test/eif_constructors.cpp

   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/utility/enable_if.hpp>
  14 #include <boost/type_traits.hpp>
  15 #include <boost/detail/lightweight_test.hpp>
  16
  17 using boost::enable_if;
  18 using boost::disable_if;
  19 using boost::is_arithmetic;
  20
  21 struct container {
  22   bool my_value;
  23
  24   template <class T>
  25   container(const T&, const typename enable_if<is_arithmetic<T>, T>::type * = 0):
  26   my_value(true) {}
  27
  28   template <class T>
  29   container(const T&, const typename disable_if<is_arithmetic<T>, T>::type * = 0):
  30   my_value(false) {}
  31 };
  32
  33 // example from Howard Hinnant (tests enable_if template members of a templated class)
  34 template <class charT>
  35 struct xstring
  36 {
  37   template <class It>
  38   xstring(It begin, It end, typename
  39           disable_if<is_arithmetic<It> >::type* = 0)
  40     : data(end-begin) {}
  41
  42   int data;
  43 };
  44
  45
  46 int main()
  47 {
  48
  49   BOOST_TEST(container(1).my_value);
  50   BOOST_TEST(container(1.0).my_value);
  51
  52   BOOST_TEST(!container("1").my_value);
  53   BOOST_TEST(!container(static_cast<void*>(0)).my_value);
  54
  55   char sa[] = "123456";
  56   BOOST_TEST(xstring<char>(sa, sa+6).data == 6);
  57
  58
  59   return boost::report_errors();
  60 }
  61