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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)
INCLUDE ’mpif.h’
MPI_IMRECV(BUF, COUNT, DATATYPE, MESSAGE, REQUEST, IERROR)
<type> BUF(*)
INTEGER OUNT, DATATYPE, MESSAGE, REQUEST, IERROR
There is no C++ binding for this function.
- 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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