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MPI_Imrecv - Non-blocking receive for a matched message
#include <mpi.h>
int MPI_Imrecv(void *buf, int count, MPI_Datatype type,
MPI_Message *message, MPI_Request *request)
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
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
- count
- Number of elements to receive (nonnegative integer).
- datatype
- Datatype of each send buffer element (handle).
- message
- Message
(handle).
- buf
- Initial address of receive buffer (choice).
- request
- Request (handle).
- IERROR
- Fortran only: Error status (integer).
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
immediately 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 issued.
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_Cancel 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 signature has matched -- and possible received -- before this
MPI_Imrecv is canceled).
This is an MPI-3 function and has no C++ binding.
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.
MPI_Mprobe
MPI_Improbe
MPI_Probe
MPI_Iprobe
MPI_Imrecv
MPI_Cancel
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