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1 | // Copyright (C) 2006 Douglas Gregor <doug.gregor -at- gmail.com>. |
2 | ||
3 | // Use, modification and distribution is subject to the Boost Software | |
4 | // License, Version 1.0. (See accompanying file LICENSE_1_0.txt or copy at | |
5 | // http://www.boost.org/LICENSE_1_0.txt) | |
6 | ||
7 | /** @file status.hpp | |
8 | * | |
9 | * This header defines the class @c status, which reports on the | |
10 | * results of point-to-point communication. | |
11 | */ | |
12 | #ifndef BOOST_MPI_STATUS_HPP | |
13 | #define BOOST_MPI_STATUS_HPP | |
14 | ||
15 | #include <boost/mpi/config.hpp> | |
20effc67 | 16 | #include <boost/mpi/datatype.hpp> |
7c673cae | 17 | #include <boost/optional.hpp> |
92f5a8d4 | 18 | #include <boost/mpl/bool.hpp> |
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19 | |
20 | namespace boost { namespace mpi { | |
21 | ||
22 | class request; | |
23 | class communicator; | |
24 | ||
25 | /** @brief Contains information about a message that has been or can | |
26 | * be received. | |
27 | * | |
28 | * This structure contains status information about messages that | |
29 | * have been received (with @c communicator::recv) or can be received | |
30 | * (returned from @c communicator::probe or @c | |
31 | * communicator::iprobe). It permits access to the source of the | |
32 | * message, message tag, error code (rarely used), or the number of | |
33 | * elements that have been transmitted. | |
34 | */ | |
35 | class BOOST_MPI_DECL status | |
36 | { | |
37 | public: | |
38 | status() : m_count(-1) { } | |
39 | ||
40 | status(MPI_Status const& s) : m_status(s), m_count(-1) {} | |
41 | ||
42 | /** | |
43 | * Retrieve the source of the message. | |
44 | */ | |
45 | int source() const { return m_status.MPI_SOURCE; } | |
46 | ||
47 | /** | |
48 | * Retrieve the message tag. | |
49 | */ | |
50 | int tag() const { return m_status.MPI_TAG; } | |
51 | ||
52 | /** | |
53 | * Retrieve the error code. | |
54 | */ | |
55 | int error() const { return m_status.MPI_ERROR; } | |
56 | ||
57 | /** | |
58 | * Determine whether the communication associated with this object | |
59 | * has been successfully cancelled. | |
60 | */ | |
61 | bool cancelled() const; | |
62 | ||
63 | /** | |
64 | * Determines the number of elements of type @c T contained in the | |
65 | * message. The type @c T must have an associated data type, i.e., | |
66 | * @c is_mpi_datatype<T> must derive @c mpl::true_. In cases where | |
67 | * the type @c T does not match the transmitted type, this routine | |
68 | * will return an empty @c optional<int>. | |
69 | * | |
70 | * @returns the number of @c T elements in the message, if it can be | |
71 | * determined. | |
72 | */ | |
20effc67 | 73 | template<typename T> optional<int> count() const { return count_impl<T>(is_mpi_datatype<T>()); } |
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74 | |
75 | /** | |
76 | * References the underlying @c MPI_Status | |
77 | */ | |
78 | operator MPI_Status&() { return m_status; } | |
79 | ||
80 | /** | |
81 | * References the underlying @c MPI_Status | |
82 | */ | |
83 | operator const MPI_Status&() const { return m_status; } | |
84 | ||
85 | private: | |
86 | /** | |
87 | * INTERNAL ONLY | |
88 | */ | |
89 | template<typename T> optional<int> count_impl(mpl::true_) const; | |
90 | ||
91 | /** | |
92 | * INTERNAL ONLY | |
93 | */ | |
94 | template<typename T> optional<int> count_impl(mpl::false_) const; | |
95 | ||
96 | public: // friend templates are not portable | |
97 | ||
98 | /// INTERNAL ONLY | |
99 | mutable MPI_Status m_status; | |
100 | mutable int m_count; | |
101 | ||
102 | friend class communicator; | |
103 | friend class request; | |
104 | }; | |
105 | ||
20effc67 TL |
106 | template<typename T> |
107 | inline optional<int> status::count_impl(mpl::true_) const | |
108 | { | |
109 | if (m_count != -1) | |
110 | return m_count; | |
111 | ||
112 | int return_value; | |
113 | BOOST_MPI_CHECK_RESULT(MPI_Get_count, | |
114 | (&m_status, get_mpi_datatype<T>(T()), &return_value)); | |
115 | if (return_value == MPI_UNDEFINED) | |
116 | return optional<int>(); | |
117 | else | |
118 | /* Cache the result. */ | |
119 | return m_count = return_value; | |
120 | } | |
121 | ||
122 | template<typename T> | |
123 | inline optional<int> status::count_impl(mpl::false_) const | |
124 | { | |
125 | if (m_count == -1) | |
126 | return optional<int>(); | |
127 | else | |
128 | return m_count; | |
129 | } | |
130 | ||
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131 | |
132 | } } // end namespace boost::mpi | |
133 | ||
134 | #endif // BOOST_MPI_STATUS_HPP |