mpi_win_start(3openmpi) [osx man page]

MPI_Win_start(3OpenMPI) 												   MPI_Win_start(3OpenMPI)

NAME

       MPI_Win_start - Starts an RMA access epoch for win

SYNTAX

C Syntax
       #include <mpi.h>
       int MPI_Win_start(MPI_Group group, int assert, MPI_Win win)

Fortran Syntax
       INCLUDE 'mpif.h'
       MPI_WIN_START(GROUP, ASSERT, WIN, IERROR)
	    INTEGER GROUP, ASSERT, WIN, IERROR

C++ Syntax
       #include <mpi.h>
       void MPI::Win::Start(const MPI::Group& group, int assert) const

INPUT PARAMETERS

       group	 The group of target processes (handle).

       assert	 Program assertion (integer).

       win	 Window object (handle).

OUTPUT PARAMETERS

       IERROR	 Fortran only: Error status (integer).

DESCRIPTION

       MPI_Win_start is a one-sided MPI communication synchronization call that starts an RMA access epoch for win. RMA calls issued on win during
       this epoch must access only windows at processes in group. Each process in group must issue a matching call to MPI_Win_post.  MPI_Win_start
       is allowed to block until the corresponding MPI_Win_post calls have been executed, but is not required to.

       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. The following assertion value is supported:

       MPI_MODE_NOCHECK
		 When this value is passed in to this call, the library assumes that the post call on the target has been called  and  it  is  not
		 necessary for the library to check to see if such a call has been made.

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_Win_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_post MPI_Win_complete

Open MPI 1.2							    March 2007						   MPI_Win_start(3OpenMPI)

MPI_Win_start(3)							MPI							  MPI_Win_start(3)

NAME

       MPI_Win_start -	Start an RMA access epoch for MPI

SYNOPSIS

       int MPI_Win_start(MPI_Group group, int assert, MPI_Win win)

INPUT PARAMETERS

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

NOTES

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

       MPI_MODE_NOCHECK
	      - the matching calls to MPI_WIN_POST have already completed on all target processes when the call to  MPI_WIN_START  is  made.   The
	      nocheck  option  can  be specified in a start call if and only if it is specified in each matching post call. This is similar to the
	      optimization of ready-send that may save a handshake when the handshake is implicit in the code. (However, ready-send is matched	by
	      a regular receive, whereas both start and post must specify the nocheck option.)

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

LOCATION

       win_start.c

								     5/20/2010							  MPI_Win_start(3)