MPI_Imrecv(3) Open MPI MPI_Imrecv(3)
NAME
MPI_Imrecv - Non-blocking receive for a matched message
SYNTAX
C Syntax
#include <mpi.h>
int MPI_Imrecv(void *buf, int count, MPI_Datatype type,
MPI_Message *message, MPI_Request *request)
Fortran Syntax
USE MPI
! or the older form: INCLUDE 'mpif.h'
MPI_IMRECV(BUF, COUNT, DATATYPE, MESSAGE, REQUEST, IERROR)
<type> BUF(*)
INTEGER COUNT, DATATYPE, MESSAGE, REQUEST, IERROR
Fortran 2008 Syntax
USE mpi_f08
MPI_Imrecv(buf, count, datatype, message, request, ierror)
TYPE(*), DIMENSION(..), ASYNCHRONOUS :: buf
INTEGER, INTENT(IN) :: count
TYPE(MPI_Datatype), INTENT(IN) :: datatype
TYPE(MPI_Message), INTENT(INOUT) :: message
TYPE(MPI_Request), INTENT(OUT) :: request
INTEGER, OPTIONAL, INTENT(OUT) :: ierror
C++ Syntax
There is no C++ binding for this function.
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).
request Request (handle).
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.
The request returned from MPI_Imrecv can be used with any of the
MPI_Test and MPI_Wait variants, like any non-blocking receive request.
If MPI_Imrecv is called with MPI_MESSAGE_NULL as the message argument,
a call to one of the MPI_Test or MPI_Wait variants will return immedi-
ately 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 is-
sued.
If reception of a matched message is started with MPI_Imrecv, then it
is possible to cancel the returned request with MPI_Cancel. If MPI_Can-
cel succeeds, the matched message must be found by a subsequent message
probe (MPI_Probe, MPI_Iprobe, MPI_Mprobe, or MPI_Improbe), received by
a subsequent receive operation or canceled by the sender.
Note, however, that is it possible for the cancellation of operations
initiated with MPI_Imrecv to fail. An example of a failing case is
when canceling the matched message receive would violate MPI message
ordering rules (e.g., if another message matching the same message sig-
nature has matched -- and possible received -- before this MPI_Imrecv
is canceled).
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++ func-
tions 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_Improbe
MPI_Probe
MPI_Iprobe
MPI_Imrecv
MPI_Cancel
4.1.2 Nov 24, 2021 MPI_Imrecv(3)
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