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MPI_Irecv.3.rst

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MPI_Irecv

MPI_Irecv Starts a standard-mode, nonblocking receive.

SYNTAX

C Syntax

#include <mpi.h>

int MPI_Irecv(void *buf, int count, MPI_Datatype datatype,
        int source, int tag, MPI_Comm comm, MPI_Request *request)

Fortran Syntax

USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_IRECV(BUF, COUNT, DATATYPE, SOURCE, TAG, COMM, REQUEST,
     IERROR)
 <type>  BUF(*)
 INTEGER COUNT, DATATYPE, SOURCE, TAG, COMM, REQUEST, IERROR

Fortran 2008 Syntax

USE mpi_f08
MPI_Irecv(buf, count, datatype, source, tag, comm, request, ierror)
 TYPE(*), DIMENSION(..), ASYNCHRONOUS :: buf
 INTEGER, INTENT(IN) :: count, source, tag
 TYPE(MPI_Datatype), INTENT(IN) :: datatype
 TYPE(MPI_Comm), INTENT(IN) :: comm
 TYPE(MPI_Request), INTENT(OUT) :: request
 INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

  • buf: Initial address of receive buffer (choice).
  • count: Number of elements in receive buffer (integer).
  • datatype: Datatype of each receive buffer element (handle).
  • source: Rank of source (integer).
  • tag: Message tag (integer).
  • comm: Communicator (handle).

OUTPUT PARAMETERS

  • request: Communication request (handle).
  • ierror: Fortran only: Error status (integer).

DESCRIPTION

Nonblocking calls allocate a communication request object and associate it with the request handle (the argument request). The request can be used later to query the status of the communication or wait for its completion.

A nonblocking receive call indicates that the system may start writing data into the receive buffer. The receiver should not access any part of the receive buffer after a nonblocking receive operation is called, until the receive completes.

A receive request can be determined being completed by calling the MPI_Wait, MPI_Waitany, MPI_Test, or MPI_Testany with request returned by this function.

ERRORS

* MPI_Recv * MPI_Probe * MPI_Test * MPI_Testany * MPI_Wait * MPI_Waitany