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 com
pleted 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 win
dow 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 For
tran, 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
ues to be returned (in C and Fortran; this error handler
is less useful in with the C++ MPI bindings. The prede
fined 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++ bind
ings 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_Accumu
late(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 infor
mation about each MPI function (most of which is not
duplicated in these man pages).
http://www.mpi-forum.org/
LOCATION
wfence.c
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