blob: 522b796fe0e637161bd728ebe901c7e2554bb00c (
plain)
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
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
|
//-----------------------------------------------------------------------------
// boost variant/detail/forced_return.hpp header file
// See http://www.boost.org for updates, documentation, and revision history.
//-----------------------------------------------------------------------------
//
// Copyright (c) 2003
// Eric Friedman
//
// Distributed under 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)
#ifndef BOOST_VARIANT_DETAIL_FORCED_RETURN_HPP
#define BOOST_VARIANT_DETAIL_FORCED_RETURN_HPP
#include "boost/config.hpp"
#include "boost/variant/detail/generic_result_type.hpp"
#include "boost/assert.hpp"
namespace boost {
namespace detail { namespace variant {
///////////////////////////////////////////////////////////////////////////////
// (detail) function template forced_return
//
// Logical error to permit invocation at runtime, but (artificially) satisfies
// compile-time requirement of returning a result value.
//
#if !defined(BOOST_MSVC) \
&& !defined(BOOST_NO_VOID_RETURNS)
// "standard" implementation:
template <typename T>
inline T forced_return()
{
// logical error: should never be here! (see above)
BOOST_ASSERT(false);
T (*dummy_function_ptr)() = 0;
return dummy_function_ptr();
}
template <>
inline void forced_return<void>()
{
// logical error: should never be here! (see above)
BOOST_ASSERT(false);
}
#elif !defined(BOOST_MSVC)
// workaround implementation
//
// TODO: Determine the most efficient way to handle this -- as below? by
// throwing? by recursive call to forced_return itself? etc.
//
template <typename T>
inline
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(T)
forced_return()
{
// logical error: should never be here! (see above)
BOOST_ASSERT(false);
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(T) (*dummy)() = 0;
return dummy();
}
#else // defined(BOOST_MSVC)
# pragma warning( push )
# pragma warning( disable : 4702 ) // unreachable code
// msvc-specific implementation
//
// Leverages __declspec(noreturn) for optimized implementation.
//
__declspec(noreturn)
inline void forced_return_no_return() {};
template <typename T>
inline
BOOST_VARIANT_AUX_GENERIC_RESULT_TYPE(T)
forced_return()
{
// logical error: should never be here! (see above)
BOOST_ASSERT(false);
forced_return_no_return();
}
# pragma warning( pop )
#endif // BOOST_MSVC optimization
}} // namespace detail::variant
} // namespace boost
#endif // BOOST_VARIANT_DETAIL_FORCED_RETURN_HPP
|
Swift