1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
|
// Boost enable_if library
// Copyright 2003 (c) The Trustees of Indiana University.
// Use, modification, and distribution is subject to the Boost Software
// License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at
// http://www.boost.org/LICENSE_1_0.txt)
// Authors: Jaakko Jarvi (jajarvi at osl.iu.edu)
// Jeremiah Willcock (jewillco at osl.iu.edu)
// Andrew Lumsdaine (lums at osl.iu.edu)
#include <boost/utility/enable_if.hpp>
#include <boost/type_traits.hpp>
#include <boost/core/lightweight_test.hpp>
using boost::enable_if;
using boost::disable_if;
using boost::is_arithmetic;
struct container {
bool my_value;
template <class T>
container(const T&, const typename enable_if<is_arithmetic<T>, T>::type * = 0):
my_value(true) {}
template <class T>
container(const T&, const typename disable_if<is_arithmetic<T>, T>::type * = 0):
my_value(false) {}
};
// example from Howard Hinnant (tests enable_if template members of a templated class)
template <class charT>
struct xstring
{
template <class It>
xstring(It begin, It end, typename
disable_if<is_arithmetic<It> >::type* = 0)
: data(end-begin) {}
int data;
};
int main()
{
BOOST_TEST(container(1).my_value);
BOOST_TEST(container(1.0).my_value);
BOOST_TEST(!container("1").my_value);
BOOST_TEST(!container(static_cast<void*>(0)).my_value);
char sa[] = "123456";
BOOST_TEST(xstring<char>(sa, sa+6).data == 6);
return boost::report_errors();
}
|
