NAME
MPI_Win_fence - Synchronizes one-sided communications on a window
SYNOPSIS
#include <mpi.h>
int
MPI_Win_fence(int assertion, MPI_Win win)
INPUT PARAMETERS
assertion
- program assertion (integer)
win - window object (handle)
NOTES
The MPI call MPI_WIN_FENCE(assert, win) synchronizes RMA calls on win.
The call is collective 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 target 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 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.
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.
ERRORS
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 exceptions
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.
MPI_SUCCESS
- No error; MPI routine completed successfully.
MPI_ERR_WIN
- Invalid window. A common error is to use a null window in a
call.
MPI_ERR_EPOCH
- 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.
MPI_ERR_OTHER
- 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_complete(3), MPI_Accumulate(3),
MPI_Win_free(3), MPI_Win_get_group(3), MPI_Win_get_group(3),
MPI_Win_wait(3)
MORE INFORMATION
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).
http://www.mpi-forum.org/
LOCATION
wfence.c