NAME

       MPI_Improbe - Non-blocking matched probe for a message.

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Improbe(int source, int tag, MPI_Comm comm,
            int *flag, MPI_Message *message, MPI_Status *status)

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_IMPROBE(SOURCE, TAG, COMM, FLAG, MESSAGE, STATUS, IERROR)
            LOGICAL   FLAG
            INTEGER   SOURCE, TAG, COMM, MESSAGE
            INTEGER   STATUS(MPI_STATUS_SIZE), IERROR

C++ Syntax

       There is no C++ binding for this function.

INPUT PARAMETERS

       source    Source rank or MPI_ANY_SOURCE (integer).

       tag       Tag value or MPI_ANY_TAG (integer).

       comm      Communicator (handle).

OUTPUT PARAMETERS

       flag      Flag (logical).

       message   Message (handle).

       status    Status object (status).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       Like  MPI_Probe  and  MPI_Iprobe, the MPI_Mprobe and MPI_Improbe operations allow incoming messages to be
       queried without actually receiving them, except that MPI_Mprobe and MPI_Improbe provide  a  mechanism  to
       receive  the  specific  message  that  was  matched  regardless  of  other  intervening  probe or receive
       operations.  This gives the application an opportunity to decide how to receive the message, based on the
       information returned by the probe.  In particular, the application may allocate memory  for  the  receive
       buffer according to the length of the probed message.

       A  matching  probe  with MPI_PROC_NULL as source returns flag = true, message = MPI_MESSAGE_NULL, and the
       status object returns source = MPI_PROC_NULL, tag = MPI_ANY_TAG, and count = 0.

       MPI_Iprobe returns a true value in flag if a message has been matched and can be received by passing  the
       message handle to the MPI_Mrecv or MPI_Imrecv functions, provided the source was not MPI_PROC_NULL.

NOTE

       This is an MPI-3 function and has no C++ binding.

ERRORS

       Almost  all  MPI  routines  return  an  error  value; C routines as the value of the function and Fortran
       routines in the last argument. C++ functions do not return errors.

       Before the error value is returned, the current MPI error handler  is  called.  By  default,  this  error
       handler  aborts  the  MPI  job,  except  for  I/O  function errors. The error handler may be changed with
       MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN may be used to cause error values
       to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.

SEE ALSO

       MPI_Mprobe
       MPI_Probe
       MPI_Iprobe
       MPI_Mrecv
       MPI_Imrecv
       MPI_Cancel

1.10.2                                            Jan 21, 2016                                    MPI_Improbe(3)