#include <mpi.h> int MPI_Win_fence(int assert, MPI_Win win)
INCLUDE 'mpif.h'
MPI_WIN_FENCE(ASSERT, WIN, IERROR)
INTEGER ASSERT, WIN, IERROR
#include <mpi.h> void MPI::Win::Fence(int assert) const
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 communication 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.
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.