MPI_Win_get_attr(3)

NAME
     MPI_Win_get_attr - Retrieves a window attribute value by key

SYNOPSIS
     C:

          #include <mpi.h>

          int MPI_Win_get_attr ( win, win_keyval, attribute_val, flag )
          MPI_Win win;
          int win_keyval;
          void *attribute_val;
          int *flag;


     Fortran:

          INCLUDE "mpif.h" (or USE MPI)

          INTEGER win, win_keyval, ierror
          INTEGER(KIND=MPI_ADDRESS_KIND) attribute_val
          LOGICAL flag

          CALL MPI_WIN_GET_ATTR(win, win_keyval, attrbute_value,
          flag, ierror)


STANDARDS
     This function is defined in the MPI-2 standard.

     This release implements the MPI 1.2 standard, as documented by the MPI
     Forum in the spring 1997 release of MPI:  A Message Passing Interface
     Standard.

DESCRIPTION
     The MPI_Win_get_attr routine retrieves a window attribute value by key.
     This routine accepts the following parameters:

     win       Specifies the window to which the attribute is attached
               (handle).

     win_keyval
               Specifies the key value (integer).

     attribute_val
               Returns the attribute value, unless flag is set to false.

     flag      Specifies the presence of an attribute value.  If an attribute
               value was extracted, flag is set to true.  If no attribute is
               associated with the key, flag is set to false.
     ierror    Specifies the return code value for successful completion,
               which is in MPI_SUCCESS.  MPI_SUCCESS is defined in the mpif.h
               file.

NOTES
     Attributes must be extracted from the same language as that in which they
     were inserted.

     For C programs, even though the attribute_val argument is declared as
     void, it is really the address of a void pointer.  See the standard for
     more details.

     For Fortran programs, the attribute_val is a pointer to a Fortran integer
     of kind MPI_ADDRESS_KIND, not a pointer to a void.

ENVIRONMENTAL INQUIRIES
     MPI predefines the following attributes attached to windows created using
     MPI_Win_create.  These attributes may not be deleted, their keys freed,
     nor their values changed.

     MPI_WIN_BASE
          Returns the base address of the window.

     MPI_WIN_SIZE
          Returns the size of the window in bytes.

     MPI_WIN_DISP_UNIT
          Returns the displacement unit associated with the window.

SEE ALSO
      MPI_Win_create(3), MPI_Win_set_attr(3), MPI_Win_delete_attr(3),
     MPI_Win_create_keyval(3), MPI_Win_free_keyval(3)