MPIWincreate(3OpenMPI) MPIWincreate(3OpenMPI)

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


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       MPIWincreate(void *base, MPIAint size, int dispunit,
            MPIInfo info, MPIComm comm, MPIWin *win)


FFoorrttrraann SSyynnttaaxx ((sseeee FFOORRTTRRAANN 7777 NNOOTTEESS))
       INCLUDE 'mpif.h'
       MPIWINCREATE(BASE, SIZE, DISPUNIT, INFO, COMM, WIN, IERROR)
             BASE(*)
            INTEGER(KIND=MPIADDRESSKIND) SIZE
            INTEGER DISPUNIT, INFO, COMM, WIN, IERROR


CC++++ SSyynnttaaxx
       #include 
       static MPI::Win MPI::Win::Create(const void* base,
            MPI::Aint size, int dispunit, const
            MPI::Info& info, const MPI::Intracomm& comm)


IINNPPUUTT PPAARRAAMMEETTEERRSS
       base      Initial address of window (choice).

       size      Size of window in bytes (nonnegative integer).

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

       info      Info argument (handle).

       comm      Communicator (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERRSS
       win       Window object returned by the call (handle).

       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPIWincreate  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  MPIWincreate  was  allocated  by
       MPIAllocmem, the size of the window can be no larger than  the  value
       set by the MPIALLOCMEM function.

       The displacement unit argument is provided to facilitate address arith-
       metic in RMA operations: the target displacement  argument  of  an  RMA
       operation  is  scaled  by  the factor dispunit specified by the target
       process, at window creation.

       The following info key is supported:

       nolocks  If MPIWinlock 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.



NNOOTTEESS
       Common choices for dispunit 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 MPIAllocmem  to  guarantee  properly  aligned
       window  boundaries  (such as word, double-word, cache line, page frame,
       and so on).





FFOORRTTRRAANN 7777 NNOOTTEESS
       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*MPIADDRESSKIND SIZE

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


EERRRROORRSS
       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::ERRORSTHROWEXCEPTIONS, 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
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       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          MPIWincreate(3OpenMPI)