Skip to content

Latest commit

 

History

History
102 lines (71 loc) · 2.77 KB

MPI_Win_shared_query.3.rst

File metadata and controls

102 lines (71 loc) · 2.77 KB
Raw

MPI_Win_shared_query

:ref:`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

:ref:`MPI_Win_shared_query` queries the process-local address for remote memory segments created with :ref:`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 section 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 :ref:`MPI_Alloc_mem` was called with size = 0.

C NOTES

The parameter baseptr is of type void * to allow passing any pointer object for this parameter. The provided argument should be a pointer to a pointer of arbitrary type (e.g. void **).

ERRORS

.. seealso::
   * :ref:`MPI_Alloc_mem`
   * :ref:`MPI_Win_allocate_shared`