mpi_win_fence(3openmpi) [osx man page]

MPI_Win_fence(3OpenMPI) 												   MPI_Win_fence(3OpenMPI)

NAME

       MPI_Win_fence - Synchronizes RMA calls on a window.

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Win_fence(int assert, MPI_Win win)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_WIN_FENCE(ASSERT, WIN, IERROR)
	    INTEGER ASSERT, WIN, IERROR

C++ Syntax
       #include <mpi.h>
       void MPI::Win::Fence(int assert) const

INPUT PARAMETERS

       assert	 Program assertion (integer).

       win	 Window object (handle).

OUTPUT PARAMETER

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Win_fence  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 tar-
       get  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.

       The call completes an RMA access epoch if it was preceded by another fence call and the local process issued RMA communication calls on win
       between	these  two  calls.  The call completes an RMA exposure epoch if it was preceded by another fence call and the local window was the
       target of RMA accesses between these two calls. The call starts an RMA access epoch if it is followed by another fence call and by RMA com-
       munication  calls  issued  between these two fence calls. The call starts an exposure epoch if it is followed by another fence call and the
       local window is the target of RMA accesses between these two fence calls. Thus, the fence call is equivalent to calls to a subset of  post,
       start, complete, wait.

       A  fence  call usually entails a barrier synchronization: a process completes a call to MPI_Win_fence only after all other processes in the
       group have entered their matching call. However, a call to MPI_Win_fence that is known not to end any epoch (in	particular,  a	call  with
       assert = MPI_MODE_NOPRECEDE) does not necessarily act as a barrier.

NOTE

       Calls to MPI_Win_fence should both precede and follow calls to put, get or accumulate that are synchronized with fence calls.

ERRORS

       Almost all MPI routines return an error value; C routines as the value of the function and Fortran routines in the last argument. C++ func-
       tions do not return errors. If the default error handler is set to MPI::ERRORS_THROW_EXCEPTIONS, then on error the C++ exception  mechanism
       will be used to throw an MPI:Exception object.

       Before  the error value is returned, the current MPI error handler is called. By default, this error handler aborts the MPI job, except for
       I/O function errors. The error handler may be changed with MPI_Comm_set_errhandler; the predefined error handler MPI_ERRORS_RETURN  may	be
       used to cause error values to be returned. Note that MPI does not guarantee that an MPI program can continue past an error.

SEE ALSO

       MPI_Win_create MPI_Win_start MPI_Win_post MPI_Win_complete MPI_Win_wait

Open MPI 1.2							    March 2007						   MPI_Win_fence(3OpenMPI)

MPI_Win_fence(3)						      LAM/MPI							  MPI_Win_fence(3)

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

LAM
/MPI 6.5.8							    11/10/2002							  MPI_Win_fence(3)