MPI_Irecv(3) Open MPI MPI_Irecv(3)
NAME
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
C++ Syntax
#include <mpi.h>
Request Comm::Irecv(void* buf, int count, const Datatype&
datatype, int source, int tag) const
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
Almost all MPI routines return an error value; C routines as the value
of the function and Fortran routines in the last argument. C++ func-
tions do not return errors. If the default error handler is set to
MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
will be used to throw an MPI::Exception object.
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_Recv MPI_Probe MPI_Test MPI_Testany MPI_Wait MPI_Waitany
4.1.2 Nov 24, 2021 MPI_Irecv(3)
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