NAME

       MPI_Get, MPI_Rget - Copies data from the target memory to the origin.

SYNTAX

C Syntax

       #include <mpi.h>
       MPI_Get(void *origin_addr, int origin_count, MPI_Datatype
            origin_datatype, int target_rank, MPI_Aint target_disp,
            int target_count, MPI_Datatype target_datatype, MPI_Win win)

       MPI_Rget(void *origin_addr, int origin_count, MPI_Datatype
             origin_datatype, int target_rank, MPI_Aint target_disp,
             int target_count, MPI_Datatype target_datatype, MPI_Win win,
                MPI_Request *request)

Fortran Syntax (see FORTRAN 77 NOTES)

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_GET(ORIGIN_ADDR, ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
            TARGET_DISP, TARGET_COUNT, TARGET_DATATYPE, WIN, IERROR)
            <type> ORIGIN_ADDR(*)
            INTEGER(KIND=MPI_ADDRESS_KIND) TARGET_DISP
            INTEGER ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
            TARGET_COUNT, TARGET_DATATYPE, WIN, IERROR

       MPI_RGET(ORIGIN_ADDR, ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
             TARGET_DISP, TARGET_COUNT, TARGET_DATATYPE, WIN, REQUEST, IERROR)
             <type> ORIGIN_ADDR(*)
             INTEGER(KIND=MPI_ADDRESS_KIND) TARGET_DISP
             INTEGER ORIGIN_COUNT, ORIGIN_DATATYPE, TARGET_RANK,
             TARGET_COUNT, TARGET_DATATYPE, WIN, REQUEST, IERROR

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Get(origin_addr, origin_count, origin_datatype, target_rank,
                 target_disp, target_count, target_datatype, win, ierror)
            TYPE(*), DIMENSION(..), ASYNCHRONOUS :: origin_addr
            INTEGER, INTENT(IN) :: origin_count, target_rank, target_count
            TYPE(MPI_Datatype), INTENT(IN) :: origin_datatype, target_datatype
            INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: target_disp
            TYPE(MPI_Win), INTENT(IN) :: win
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

       MPI_Rget(origin_addr, origin_count, origin_datatype, target_rank,
            target_disp, target_count, target_datatype, win, request,
                 ierror)
            TYPE(*), DIMENSION(..), ASYNCHRONOUS :: origin_addr
            INTEGER, INTENT(IN) :: origin_count, target_rank, target_count
            TYPE(MPI_Datatype), INTENT(IN) :: origin_datatype, target_datatype
            INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(IN) :: target_disp
            TYPE(MPI_Win), INTENT(IN) :: win
            TYPE(MPI_Request), INTENT(OUT) :: request
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

C++ Syntax

       #include <mpi.h>
       void MPI::Win::Get(const void *origin_addr, int origin_count,
            const MPI::Datatype& origin_datatype, int target_rank,
            MPI::Aint target_disp, int target_count,
            const MPI::Datatype& target_datatype) const

INPUT PARAMETERS

       origin_addr
                 Initial address of origin buffer (choice).

       origin_count
                 Number of entries in origin buffer (nonnegative integer).

       origin_datatype
                 Data type of each entry in origin buffer (handle).

       target_rank
                 Rank of target (nonnegative integer).

       target_disp
                 Displacement from window start to the beginning of the target buffer (nonnegative integer).

       target_count
                 Number of entries in target buffer (nonnegative integer).

       target datatype
                 datatype of each entry in target buffer (handle)

       win       window object used for communication (handle)

OUTPUT PARAMETER

       request   MPI_Rget: RMA request

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_Get  copies  data from the target memory to the origin, similar to MPI_Put, except that the direction
       of data transfer is reversed. The origin_datatype may not  specify  overlapping  entries  in  the  origin
       buffer.  The  target  buffer  must  be  contained within the target window, and the copied data must fit,
       without truncation, in the origin buffer. Only processes within the  same  node  can  access  the  target
       window.

       MPI_Rget is similar to MPI_Get, except that it allocates a communication request object and associates it
       with  the  request  handle  (the  argument  request) that can be used to wait or test for completion. The
       completion of an MPI_Rget operation indicates that the  data  is  available  in  the  origin  buffer.  If
       origin_addr points to memory attached to a window, then the data becomes available in the private copy of
       this window.

FORTRAN 77 NOTES

       The  MPI  standard  prescribes  portable Fortran syntax for the TARGET_DISP argument only for Fortran 90.
       FORTRAN 77 users may use the non-portable syntax

            INTEGER*MPI_ADDRESS_KIND TARGET_DISP

       where MPI_ADDRESS_KIND is a constant defined in mpif.h and gives the length of the  declared  integer  in
       bytes.

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_Put

4.1.6                                             Sep 30, 2023                                        MPI_Get(3)