MPI_Win_fence(3) LAM/MPI MPI_Win_fence(3)
MPI_Win_fence - Synchronizes one-sided communications on a window
MPI_Win_fence(int assertion, MPI_Win win)
- program assertion (integer)
win - window object (handle)
The MPI call MPI_WIN_FENCE(assert, win) synchronizes RMA calls on win. The call is collec-
tive on the group of win. All RMA operations on win originating at a given process and
started before the fence call will complete at that process before the fence call returns.
They will be completed at their target before the fence call returns at the target. RMA
operations on win started by a process after the fence call returns will access their tar-
get window only after MPI_WIN_FENCE has been called by the target process.
Calls to MPI_WIN_FENCE should both precede and follow calls to put, get or accumulate that
are synchronized with fence calls.
NOTES FOR FORTRAN
All MPI routines in Fortran (except for MPI_WTIME and MPI_WTICK ) have an additional argu-
ment 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.
USAGE WITH IMPI EXTENSIONS
The IMPI standard only supports MPI-1 functions. Hence, this function is currently not
designed to operate within an IMPI job.
If an error occurs in an MPI function, the current MPI error handler is called to handle
it. By default, this error handler aborts the MPI job. The error handler may be changed
with MPI_Errhandler_set ; the predefined error handler MPI_ERRORS_RETURN may be used to
cause error values to be returned (in C and Fortran; this error handler is less useful in
with the C++ MPI bindings. The predefined error handler MPI::ERRORS_THROW_EXCEPTIONS
should be used in C++ if the error value needs to be recovered). Note that MPI does not
guarantee that an MPI program can continue past an error.
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. The C++ bindings for
MPI do not return error values; instead, error values are communicated by throwing excep-
tions of type MPI::Exception (but not by default). Exceptions are only thrown if the
error value is not MPI::SUCCESS
Note that if the MPI::ERRORS_RETURN handler is set in C++, while MPI functions will return
upon an error, there will be no way to recover what the actual error value was.
- No error; MPI routine completed successfully.
- Invalid window. A common error is to use a null window in a call.
- This error indicates than an operation has been attempted on a "closed" window.
Certain one-sided operations can only be performed on windows whose epoch has been
started with MPI_Win_start.
- Other error; use MPI_Error_string to get more information about this error code.
seealso MPI_Put(3), MPI_Get(3), MPI_Win_create(3), MPI_Win_start(3), MPI_Win_com-
plete(3), MPI_Accumulate(3), MPI_Win_free(3), MPI_Win_get_group(3),
For more information, please see the official MPI Forum web site, which contains the text
of both the MPI-1 and MPI-2 standards. These documents contain detailed information about
each MPI function (most of which is not duplicated in these man pages).
LAM/MPI 6.5.8 11/10/2002 MPI_Win_fence(3)