NAME

       MPI_Win_shared_query -  Query the size and base pointer for a patch of a shared memory window.

SYNOPSIS

       int MPI_Win_shared_query(MPI_Win win, int rank, MPI_Aint *size, int *disp_unit, void *baseptr)

       This   function   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 3.0,
       Section 11.7. This function can only be called with windows  of  type  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.

INPUT PARAMETERS

       win    - window object used for communication (handle)
       rank   - target rank

OUTPUT PARAMETERS

       size   - size of the segment at the given rank
       disp_unit
              - local unit size for displacements, in bytes (positive integer)
       baseptr
              - base pointer in the calling process' address space of the shared segment belonging to the target
              rank.

THREAD AND INTERRUPT SAFETY

       This routine is thread-safe.  This means that this routine may be safely used by multiple threads without
       the  need  for  any  user-provided thread locks.  However, the routine is not interrupt safe.  Typically,
       this is due to the use of memory allocation routines such as malloc or other non-MPICH  runtime  routines
       that are themselves not interrupt-safe.

NOTES FOR FORTRAN

       All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argument ierr at the
       end of the argument list.  ierr is an integer and has the same meaning as the return value of the routine
       in C.  In Fortran, MPI routines are subroutines, and are invoked with the call statement.

       All MPI objects (e.g., MPI_Datatype , MPI_Comm ) are of type INTEGER in Fortran.

ERRORS

       All  MPI routines (except MPI_Wtime and MPI_Wtick ) return an error value; C routines as the value of the
       function and Fortran routines in the last argument.  Before the value is returned, the current MPI  error
       handler  is called.  By default, this error handler aborts the MPI job.  The error handler may be changed
       with   MPI_Comm_set_errhandler   (for   communicators),   MPI_File_set_errhandler   (for   files),    and
       MPI_Win_set_errhandler  (for  RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but its use
       is deprecated.  The predefined error handler MPI_ERRORS_RETURN may be used to cause error  values  to  be
       returned.   Note that MPI does not guarentee that an MPI program can continue past an error; however, MPI
       implementations will attempt to continue whenever possible.

       MPI_SUCCESS
              - No error; MPI routine completed successfully.
       MPI_ERR_ARG
              - Invalid argument.  Some argument is invalid and is not identified  by  a  specific  error  class
              (e.g., MPI_ERR_RANK ).
       MPI_ERR_RANK
              - Invalid source or destination rank.  Ranks must be between zero and the size of the communicator
              minus  one;  ranks  in  a  receive  (  MPI_Recv  ,  MPI_Irecv  ,  MPI_Sendrecv , etc.) may also be
              MPI_ANY_SOURCE .

       MPI_ERR_WIN
              - Invalid MPI window object

SEE ALSO

       MPI_Win_allocate_shared

                                                    11/9/2015                            MPI_Win_shared_query(3)