mpi_win_lock(3openmpi) [osx man page]

MPI_Win_lock(3OpenMPI)													    MPI_Win_lock(3OpenMPI)

NAME

       MPI_Win_lock - Starts an RMA access epoch locking access to a particular rank.

SYNTAX

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

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_WIN_LOCK(LOCK_TYPE, RANK, ASSERT, WIN, IERROR)
	    INTEGER LOCK_TYPE, RANK, ASSERT, WIN, IERROR

C++ Syntax
       #include <mpi.h>
       void MPI::Win::Lock(int lock_type, int rank, int assert) const

INPUT PARAMETERS

       lock_type Either MPI_LOCK_EXCLUSIVE or MPI_LOCK_SHARED (state).

       rank	 Rank of locked window (nonnegative integer).

       assert	 Program assertion (integer).

       win	 Window object (handle).

OUTPUT PARAMETER

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       Starts  an RMA access epoch. Locks ensure that only the windows created by specific processes can be accessed by those processes (and by no
       other processes) during that epoch.

       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
       exclusive lock will not be concurrent at the window site with other accesses to the same window that are lock protected. Accesses that  are
       protected by a shared lock will not be concurrent at the window site with accesses protected by an exclusive lock to the same window.

       The assert argument is used to provide assertions on the context of the call that may be used for various optimizations. (See Section 6.4.4
       of the MPI-2 Standard.) A value of assert = 0 is always valid.

NOTES

       In a client/server environment in which clients connect to a server and create windows that span both the  client  and  the  server,  if  a
       client  or  server  that  has  obtained	a  lock on such a window and then terminates abnormally, the server or other clients may hang in a
       MPI_Win_lock call, failing to notice that the peer MPI job has terminated.

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_unlock

Open MPI 1.2							    March 2007						    MPI_Win_lock(3OpenMPI)

Check Out this Related Man Page

MPI_Win_unlock(3)							MPI							 MPI_Win_unlock(3)

NAME

       MPI_Win_unlock -  Completes an RMA access epoch at the target process

SYNOPSIS

       int MPI_Win_unlock(int rank, MPI_Win win)

INPUT PARAMETERS

       rank   - rank of window (nonnegative integer)
       win    - window object (handle)

THREAD AND INTERRUPT SAFETY

       This  routine  is  thread-safe.	This means that this routine may be safely used by multiple threads without the need for any user-provided
       thread locks.  However, the routine is not interrupt safe.  Typically, this is due to the use of memory allocation routines such as  malloc
       or other non-MPICH runtime routines that are themselves not interrupt-safe.

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.

ERRORS

       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.  Before the value is returned, the current MPI error handler is called.  By default, this error handler aborts  the  MPI
       job.   The  error  handler  may	be  changed  with  MPI_Comm_set_errhandler  (for  communicators), MPI_File_set_errhandler (for files), and
       MPI_Win_set_errhandler (for RMA windows).  The MPI-1 routine MPI_Errhandler_set may be used but its  use  is  deprecated.   The	predefined
       error handler MPI_ERRORS_RETURN may be used to cause error values to be returned.  Note that MPI does not guarentee that an MPI program can
       continue past an error; however, MPI implementations will attempt to continue whenever possible.

       MPI_SUCCESS
	      - No error; MPI routine completed successfully.
       MPI_ERR_RANK
	      - Invalid source or destination rank.  Ranks must be between zero and the size of the communicator minus one; ranks in a	receive  (
	      MPI_Recv , MPI_Irecv , MPI_Sendrecv , etc.) may also be MPI_ANY_SOURCE .

       MPI_ERR_WIN
	      - Invalid MPI window object
       MPI_ERR_OTHER
	      - Other error; use MPI_Error_string to get more information about this error code.

SEE ALSO

       MPI_Win_lock

LOCATION

       win_unlock.c

								     2/28/2011							 MPI_Win_unlock(3)

Linux and UNIX Man Pages

mpi_win_lock(3openmpi) [osx man page]

Check Out this Related Man Page