NAME

       MPI_Win_shared_query - Query a shared memory window

SYNTAX

C Syntax

       #include <mpi.h>
       int MPI_Win_shared_query (MPI_Win win, int rank, MPI_Aint *size,
                                 int *disp_unit, void *baseptr)

Fortran Syntax

       USE MPI
       ! or the older form: INCLUDE 'mpif.h'
       MPI_WIN_SHARED_QUERY(WIN, RANK, SIZE, DISP_UNIT, BASEPTR, IERROR)
               INTEGER WIN, RANK, DISP_UNIT, IERROR
               INTEGER(KIND=MPI_ADDRESS_KIND) SIZE, BASEPTR

Fortran 2008 Syntax

       USE mpi_f08
       MPI_Win_shared_query(win, rank, size, disp_unit, baseptr, ierror)
            USE, INTRINSIC :: ISO_C_BINDING, ONLY : C_PTR
            TYPE(MPI_Win), INTENT(IN) :: win
            INTEGER, INTENT(IN) :: rank
            INTEGER(KIND=MPI_ADDRESS_KIND), INTENT(OUT) :: size
            INTEGER, INTENT(OUT) :: disp_unit
            TYPE(C_PTR), INTENT(OUT) :: baseptr
            INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT PARAMETERS

       win       Shared memory window object (handle).

       rank      Rank in the group of window win (non-negative integer) or MPI_PROC_NULL.

OUTPUT PARAMETERS

       size      Size of the window segment (non-negative integer).

       disp_unit Local unit size for displacements, in bytes (positive integer).

       baseptr   Address for load/store access to window segment (choice).

       IERROR    Fortran only: Error status (integer).

DESCRIPTION

       MPI_Win_shared_query   queries  the  process-local  address  for  remote  memory  segments  created  with
       MPI_Win_allocate_shared. This function can return different process-local addresses for the same physical
       memory  on  different  processes.  The returned memory can be used for load/store accesses subject to the
       constraints defined in MPI-3.1 §  11.7.  This  function  can  only  be  called  with  windows  of  flavor
       MPI_WIN_FLAVOR_SHARED.   If  the  passed  window  is  not  of  flavor  MPI_WIN_FLAVOR_SHARED,  the  error
       MPI_ERR_RMA_FLAVOR is raised. When rank is MPI_PROC_NULL, the pointer, disp_unit, and size  returned  are
       the pointer, disp_unit, and size of the memory segment belonging the lowest rank that specified size > 0.
       If all processes in the group attached to the window specified size = 0, then the call returns size  =  0
       and a baseptr as if MPI_Alloc_mem was called with size = 0.

ERRORS

       Almost  all  MPI  routines  return  an  error  value; C routines as the value of the function and Fortran
       routines in the last argument.

       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_Alloc_mem MPI_Win_allocate_shared