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MPI_Win_create(3) man page (version 1.2.9)

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NAME

       MPI_Win_create  -  One-sided  MPI call that returns a window object for
       RMA operations.

SYNTAX


C Syntax

       #include <mpi.h>
       MPI_Win_create(void *base, MPI_Aint size, int disp_unit,
            MPI_Info info, MPI_Comm comm, MPI_Win *win)

Fortran Syntax (see FORTRAN 77 NOTES)

       INCLUDE 'mpif.h'
       MPI_WIN_CREATE(BASE, SIZE, DISP_UNIT, INFO, COMM, WIN, IERROR)
            <type> BASE(*)
            INTEGER(KIND=MPI_ADDRESS_KIND) SIZE
            INTEGER DISP_UNIT, INFO, COMM, WIN, IERROR

C++ Syntax

       #include <mpi.h>
       static MPI::Win MPI::Win::Create(const void* base,
            MPI::Aint size, int disp_unit, const
            MPI::Info& info, const MPI::Intracomm& comm)

INPUT PARAMETERS

       base      Initial address of window (choice).

       size      Size of window in bytes (nonnegative integer).

       disp_unit Local unit size for displacements, in bytes  (positive  inte-
                 ger).

       info      Info argument (handle).

       comm      Communicator (handle).

OUTPUT PARAMETERS

       win       Window object returned by the call (handle).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_Win_create  is  a  one-sided MPI communication collective call exe-
       cuted by all processes in the group of comm. It returns a window object
       that  can  be  used  by these processes to perform RMA operations. Each
       process specifies a window of existing memory that it  exposes  to  RMA
       accesses  by the processes in the group of comm. The window consists of
       size bytes, starting at address base. A process may elect to expose  no
       memory by specifying size = 0.

       If   the   base   value   used   by  MPI_Win_create  was  allocated  by
       MPI_Alloc_mem, the size of the window can be no larger than  the  value
       set by the MPI_ALLOC_MEM function.
       no_locks  If MPI_Win_lock is called on a window created with this  info
                 key,  the  call will fail. If this info key is present, it is
                 assumed that the local window is never locked, allowing  sev-
                 eral  internal  checks to be skipped, permitting a more effi-
                 cient implementation.

NOTES

       Common choices for disp_unit are 1 (no  scaling),  and  (in  C  syntax)
       sizeof(type),  for  a  window  that consists of an array of elements of
       type type. The later choice will allow one to use array indices in  RMA
       calls, and have those scaled correctly to byte displacements, even in a
       heterogeneous environment.

       Use memory allocated by MPI_Alloc_mem  to  guarantee  properly  aligned
       window  boundaries  (such as word, double-word, cache line, page frame,
       and so on).

FORTRAN 77 NOTES

       The MPI standard prescribes portable Fortran syntax for the SIZE  argu-
       ment  only  for  Fortran  90. FORTRAN 77 users may use the non-portable
       syntax

            INTEGER*MPI_ADDRESS_KIND SIZE

       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++  func-
       tions  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.

Open MPI 1.2                      March 2007          MPI_Win_create(3OpenMPI)

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