MPI_Imrecv - Non-blocking receive for a matched message
188.8.131.52.1. C Syntax
#include <mpi.h> int MPI_Imrecv(void *buf, int count, MPI_Datatype type, MPI_Message *message, MPI_Request *request)
184.108.40.206.2. 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
220.127.116.11.3. 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
18.104.22.168. INPUT PARAMETERS
count: Number of elements to receive (nonnegative integer).
datatype: Datatype of each send buffer element (handle).
message: Message (handle).
22.214.171.124. OUTPUT PARAMETERS
buf: Initial address of receive buffer (choice).
request: Request (handle).
IERROR: Fortran only: Error status (integer).
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).
Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument.
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.