MPI_Irsend(3)                      Open MPI                      MPI_Irsend(3)



NAME
       MPI_Irsend - Starts a ready-mode nonblocking send.


SYNTAX
C Syntax
       #include <mpi.h>
       int MPI_Irsend(void *buf, int count, MPI_Datatype datatype, int dest,
            int tag, MPI_Comm comm, MPI_Request *request)


Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_IRSEND(BUF, COUNT, DATATYPE, DEST, TAG, COMM, REQUEST, IERROR)
            <type>    BUF(*)
            INTEGER   COUNT, DATATYPE, DEST, TAG, COMM, REQUEST, IERROR


C++ Syntax
       #include <mpi.h>
       Request Comm::Irsend(const void* buf, int count, const
            Datatype& datatype, int dest, int tag) const


INPUT PARAMETERS
       buf       Initial address of send buffer (choice).

       count     Number of elements in send buffer (integer).

       datatype  Datatype of each send buffer element (handle).

       dest      Rank of destination (integer).

       tag       Message tag (integer).

       comm      Communicator (handle).


OUTPUT PARAMETERS
       request   Communication request (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPI_Irsend starts a ready-mode nonblocking send. Nonblocking calls
       allocate a communication request object and associate it with the
       request handle (the argument request). The request can be used later to
       query the status of the communication or to wait for its completion.

       A nonblocking send call indicates that the system may start copying
       data out of the send buffer. The sender should not access any part of
       the send buffer after a nonblocking send operation is called, until the
       send completes.


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++
       functions do not return errors. If the default error handler is set to
       MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception mechanism
       will be used to throw an MPI:Exception object.

       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_Rsend



1.4.1                            Jan 14, 2010                    MPI_Irsend(3)
