MPI_Win_fence − Perform an MPI fence synchronization on a MPI window
int MPI_Win_fence(int assert, MPI_Win win)
- program assertion (integer)
- window object (handle)
assert argument is used to indicate special
conditions for the fence that an implementation may use to
optimize the MPI_Win_fence operation. The value zero
is always correct. Other assertion values may be or’ed
together. Assertions that are valid for MPI_Win_fence
- the local window was not updated by local stores (or local get or receive calls) since last synchronization.
- the local window will not be updated by put or accumulate calls after the fence call, until the ensuing (fence) synchronization.
- the fence does not complete any sequence of locally issued RMA calls. If this assertion is given by any process in the window group, then it must be given by all processes in the group.
- the fence does not start any sequence of locally issued RMA calls. If the assertion is given by any process in the window group, then it must be given by all processes in the group.
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.
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.
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.
- No error; MPI routine completed successfully.
- Other error; use MPI_Error_string to get more information about this error code.
- Invalid MPI window object