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MPI_Win_lock_all(3)		      MPI		   MPI_Win_lock_all(3)

NAME
       MPI_Win_lock_all	 -   Begin an RMA access epoch at all processes	on the
       given window.

SYNOPSIS
       int MPI_Win_lock_all(int	assert,	MPI_Win	win)

       Starts an RMA access epoch to all processes in win, with	a lock type of
       MPI_Lock_shared .  During the epoch, the	calling	process	can access the
       window memory on	all processes in win by	using RMA operations. A	window
       locked with MPI_Win_lock_all must be unlocked with MPI_Win_unlock_all .
       This routine is not collective -- the ALL refers	to a lock on all  mem-
       bers of the group of the	window.

INPUT PARAMETERS
       assert -	 Used  to  optimize  this call;	zero may be used as a default.
	      See notes. (integer)
       win    -	window object (handle)

NOTES
       This call is not	collective.

       The assert argument is used to  indicate	 special  conditions  for  the
       fence  that  an implementation may use to optimize the MPI_Win_lock_all
       operation.  The value zero is always correct.  Other  assertion	values
       may  be or'ed together.	Assertions that	are valid for MPI_Win_lock_all
       are:

       MPI_MODE_NOCHECK

	      -	No other process holds,	or will	attempt	to acquire a conflict-
	      ing lock,	while the caller holds the window lock.	This is	useful
	      when mutual exclusion is achieved	by other means,	but the	coher-
	      ence  operations	that  may  be  attached	to the lock and	unlock
	      calls are	still required.

	      There  may  be  additional  overheads  associated	  with	 using
	      MPI_Win_lock  and	MPI_Win_lock_all concurrently on the same win-
	      dow. These overheads could be avoided by specifying  the	asser-
	      tion MPI_MODE_NOCHECK when possible

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 com-
       municators), MPI_File_set_errhandler (for files),  and  MPI_Win_set_er-
       rhandler	 (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 when-
       ever 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 re-
	      ceive ( 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_unlock_all

				   11/9/2015		   MPI_Win_lock_all(3)

NAME | SYNOPSIS | INPUT PARAMETERS | NOTES | THREAD AND INTERRUPT SAFETY | NOTES FOR FORTRAN | ERRORS | SEE ALSO

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