MPI_Imrecv - Non-blocking receive for a matched message
220.127.116.11.1. C Syntax
#include <mpi.h> int MPI_Imrecv(void *buf, int count, MPI_Datatype type, MPI_Message *message, MPI_Request *request)
18.104.22.168.2. 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
22.214.171.124.3. 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
126.96.36.199. INPUT PARAMETERS
count: Number of elements to receive (nonnegative integer).
datatype: Datatype of each send buffer element (handle).
message: Message (handle).
188.8.131.52. OUTPUT PARAMETERS
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
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 return result of the function and Fortran routines in the last argument.
Before the error value is returned, the current MPI error handler associated with the communication object (e.g., communicator, window, file) is called. If no communication object is associated with the MPI call, then the call is considered attached to MPI_COMM_SELF and will call the associated MPI error handler. When MPI_COMM_SELF is not initialized (i.e., before MPI_Init/MPI_Init_thread, after MPI_Finalize, or when using the Sessions Model exclusively) the error raises the initial error handler. The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF when using the World model, or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/MPI_Comm_spawn_multiple. If no other appropriate error handler has been set, then the MPI_ERRORS_RETURN error handler is called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all other MPI functions.
Open MPI includes three predefined error handlers that can be used:
MPI_ERRORS_ARE_FATALCauses the program to abort all connected MPI processes.
MPI_ERRORS_ABORTAn error handler that can be invoked on a communicator, window, file, or session. When called on a communicator, it acts as if MPI_Abort was called on that communicator. If called on a window or file, acts as if MPI_Abort was called on a communicator containing the group of processes in the corresponding window or file. If called on a session, aborts only the local process.
MPI_ERRORS_RETURNReturns an error code to the application.
MPI applications can also implement their own error handlers by calling:
MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init
Note that MPI does not guarantee that an MPI program can continue past an error.
See the MPI man page for a full list of MPI error codes.
See the Error Handling section of the MPI-3 standard for more information.