boost/mpi/status.hpp

   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>
  16 #include <boost/optional.hpp>
  17
  18 namespace boost { namespace mpi {
  19
  20 class request;
  21 class communicator;
  22
  23 /** @brief Contains information about a message that has been or can
  24  *  be received.
  25  *
  26  *  This structure contains status information about messages that
  27  *  have been received (with @c communicator::recv) or can be received
  28  *  (returned from @c communicator::probe or @c
  29  *  communicator::iprobe). It permits access to the source of the
  30  *  message, message tag, error code (rarely used), or the number of
  31  *  elements that have been transmitted.
  32  */
  33 class BOOST_MPI_DECL status
  34 {
  35  public:
  36   status() : m_count(-1) { }
  37
  38   status(MPI_Status const& s) : m_status(s), m_count(-1) {}
  39
  40   /**
  41    * Retrieve the source of the message.
  42    */
  43   int source() const { return m_status.MPI_SOURCE; }
  44
  45   /**
  46    * Retrieve the message tag.
  47    */
  48   int tag() const { return m_status.MPI_TAG; }
  49
  50   /**
  51    * Retrieve the error code.
  52    */
  53   int error() const { return m_status.MPI_ERROR; }
  54
  55   /**
  56    * Determine whether the communication associated with this object
  57    * has been successfully cancelled.
  58   */
  59   bool cancelled() const;
  60
  61   /**
  62    * Determines the number of elements of type @c T contained in the
  63    * message. The type @c T must have an associated data type, i.e.,
  64    * @c is_mpi_datatype<T> must derive @c mpl::true_. In cases where
  65    * the type @c T does not match the transmitted type, this routine
  66    * will return an empty @c optional<int>.
  67    *
  68    * @returns the number of @c T elements in the message, if it can be
  69    * determined.
  70    */
  71   template<typename T> optional<int> count() const;
  72
  73   /**
  74    * References the underlying @c MPI_Status
  75    */
  76   operator       MPI_Status&()       { return m_status; }
  77
  78   /**
  79    * References the underlying @c MPI_Status
  80    */
  81   operator const MPI_Status&() const { return m_status; }
  82
  83  private:
  84   /**
  85    * INTERNAL ONLY
  86    */
  87   template<typename T> optional<int> count_impl(mpl::true_) const;
  88
  89   /**
  90    * INTERNAL ONLY
  91    */
  92   template<typename T> optional<int> count_impl(mpl::false_) const;
  93
  94  public: // friend templates are not portable
  95
  96   /// INTERNAL ONLY
  97   mutable MPI_Status m_status;
  98   mutable int m_count;
  99
 100   friend class communicator;
 101   friend class request;
 102 };
 103
 104
 105 } } // end namespace boost::mpi
 106
 107 #endif // BOOST_MPI_STATUS_HPP