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