Linux and UNIX Man Pages

Linux & Unix Commands - Search Man Pages

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)

Check Out this Related Man Page

MPI_Win_unlock(3OpenMPI)												  MPI_Win_unlock(3OpenMPI)

NAME
MPI_Win_unlock - Completes an RMA access epoch started by a call to MPI_Win_lock. SYNTAX
C Syntax #include <mpi.h> int MPI_Win_unlock(int rank, MPI_Win win) Fortran Syntax INCLUDE 'mpif.h' MPI_WIN_UNLOCK(RANK, WIN, IERROR) INTEGER RANK, WIN, IERROR C++ Syntax #include <mpi.h> void MPI::Win::Unlock(int rank) const INPUT PARAMETERS
rank Rank of window (nonnegative integer). win Window object (handle). OUTPUT PARAMETER
IERROR Fortran only: Error status (integer). DESCRIPTION
MPI_Win_unlock completes an RMA access epoch started by a call to MPI_Win_lock. RMA operations issued during this period will have com- pleted both at the origin and at the target when the call returns. Locks are used to protect accesses to the locked target window effected by RMA calls issued between the lock and unlock call, and to pro- tect local load/store accesses to a locked local window executed between the lock and unlock call. Accesses that are protected by an exclu- sive lock will not be concurrent at the window site with other accesses to the same window that are lock protected. Accesses that are pro- tected by a shared lock will not be concurrent at the window site with accesses protected by an exclusive lock to the same window. 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_lock Open MPI 1.2 March 2007 MPI_Win_unlock(3OpenMPI)
Man Page