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MPI_Mprobe(3) man page (version 1.8.1)

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Table of Contents

Name

MPI_Mprobe - Blocking matched probe for a message.

Syntax

C Syntax


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

Fortran Syntax


INCLUDE ’mpif.h’
MPI_MPROBE(SOURCE, TAG, COMM, MESSAGE, STATUS, IERROR)
    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

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 opera- tions 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 message = MPI_MESSAGE_NULL, and the status object returns source = MPI_PROC_NULL, tag = MPI_ANY_TAG, and count = 0.

When MPI_Mprobe returns (from a non-MPI_PROC_NULL source), the matched message can then be received by passing the message handle to the MPI_Mrecv or MPI_Imrecv functions.

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_Improbe
MPI_Probe
MPI_Iprobe
MPI_Mrecv
MPI_Imrecv
MPI_Cancel

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