MPIWinfence(3OpenMPI) MPIWinfence(3OpenMPI)

NAME
       MMPPIIWWiinnffeennccee - Synchronizes RMA calls on a window.


SSYYNNTTAAXX
CC SSyynnttaaxx
       #include 
       int MPIWinfence(int assert, MPIWin win)


FFoorrttrraann SSyynnttaaxx
       INCLUDE 'mpif.h'
       MPIWINFENCE(ASSERT, WIN, IERROR)
            INTEGER ASSERT, WIN, IERROR


CC++++ SSyynnttaaxx
       #include 
       void MPI::Win::Fence(int assert) const


IINNPPUUTT PPAARRAAMMEETTEERRSS
       assert    Program assertion (integer).

       win       Window object (handle).


OOUUTTPPUUTT PPAARRAAMMEETTEERR
       IERROR    Fortran only: Error status (integer).


DESCRIPTION
       MPIWinfence  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 MPIWinfence 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 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  com-
       pletes  a  call  to MPIWinfence only after all other processes in the
       group  have  entered  their  matching  call.   However,   a   call   to
       MPIWinfence that is known not to end any epoch (in particular, a call
       with assert = MPIMODENOPRECEDE) does not necessarily act  as  a  bar-
       rier.


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




EERRRROORRSS
       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::ERRORSTHROWEXCEPTIONS, 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
       MPICommseterrhandler; the predefined error handler MPIERRORSRETURN
       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
       MPIWincreate MPIWinstart MPIWinpost MPIWincomplete MPIWinwait




Open MPI 1.2                      March 2007           MPIWinfence(3OpenMPI)