plucky (3) MPI_Mrecv.openmpi.3.gz

SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_Mrecv(void *buf, int count, MPI_Datatype type,
               MPI_Message *message, MPI_Status *status)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'
          MPI_MRECV(BUF, COUNT, DATATYPE, MESSAGE, STATUS, IERROR)
               <type>  BUF(*)
               INTEGER COUNT, DATATYPE, MESSAGE
               INTEGER STATUS(MPI_STATUS_SIZE), IERROR

   Fortran 2008 Syntax
          USE mpi_f08
          MPI_Mrecv(buf, count, datatype, message, status, ierror)
               TYPE(*), DIMENSION(..) :: buf
               INTEGER, INTENT(IN) :: count
               TYPE(MPI_Datatype), INTENT(IN) :: datatype
               TYPE(MPI_Message), INTENT(INOUT) :: message
               TYPE(MPI_Status) :: status
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

       • count: Number of elements to receive (nonnegative integer).

       • datatype: Datatype of each send buffer element (handle).

       • message: Message (handle).

OUTPUT PARAMETERS

       • buf: Initial address of receive buffer (choice).

       • status: Status object (status).

       • ierror: Fortran only: Error status (integer).

DESCRIPTION

       The  functions  MPI_Mrecv and MPI_Imrecv receive messages that have been previously matched by a matching
       probe.

       If MPI_Mrecv is called with MPI_MESSAGE_NULL as the message argument, the call returns  immediately  with
       the  status  object set to source = MPI_PROC_NULL, tag = MPI_ANY_TAG, and count = 0, as if a receive from
       MPI_PROC_NULL was issued.

       If your application does not need to examine the status field,  you  can  save  resources  by  using  the
       predefined constant MPI_STATUS_IGNORE as a special value for the status argument.

ERRORS

       Almost  all  MPI  routines  return  an  error  value; C routines as the return result of the function and
       Fortran routines in the last argument.

       Before the error value is returned, the current MPI  error  handler  associated  with  the  communication
       object  (e.g.,  communicator, window, file) is called.  If no communication object is associated with the
       MPI call, then the call is considered attached to MPI_COMM_SELF and will call the  associated  MPI  error
       handler.   When   MPI_COMM_SELF   is   not  initialized  (i.e.,  before  MPI_Init/MPI_Init_thread,  after
       MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial  error  handler.
       The  initial  error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using
       the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info  key  to  MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.   If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN
       error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is  called  for  all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called on a communicator, it acts as if MPI_Abort was called on  that  communicator.  If  called  on  a
         window  or file, acts as if MPI_Abort was called on a communicator containing the group of processes in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

       Note that per the “Return Status” section in  the  “Point-to-Point  Communication”  chapter  in  the  MPI
       Standard,  MPI  errors  on  messages  received  by MPI_Mrecv do not set the status.MPI_ERROR field in the
       returned status.  The error code is always passed to the back-end error handler and may be passed back to
       the  caller  through  the  return  value  of  MPI_Mrecv  if  the  back-end error handler returns it.  The
       pre-defined MPI error handler MPI_ERRORS_RETURN exhibits this behavior, for example.

       SEE ALSO:

          • MPI_Mprobe

          • MPI_Improbe

          • MPI_Probe

          • MPI_Iprobe

          • MPI_Imrecv

          • MPI_Cancel

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                                      MPI_MRECV(3)