NAME

       MPI_Isend - Starts a standard-mode, nonblocking send.

SYNTAX

C Syntax

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

Fortran Syntax

       INCLUDE 'mpif.h'
       MPI_ISEND(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::Isend(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_Isend   starts  a  standard-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 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.

       A send request can be determined being completed by  calling  the  MPI_Wait,  MPI_Waitany,
       MPI_Test, or MPI_Testany with request returned by this function.

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_Send MPI_Wait MPI_Waitany MPI_Test MPI_Testany