plucky (3) MPI_Win_start.openmpi.3.gz

SYNTAX

   C Syntax
          #include <mpi.h>

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

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'
          MPI_WIN_START(GROUP, ASSERT, WIN, IERROR)
               INTEGER GROUP, ASSERT, WIN, IERROR

   Fortran 2008 Syntax
          USE mpi_f08
          MPI_Win_start(group, assert, win, ierror)
               TYPE(MPI_Group), INTENT(IN) :: group
               INTEGER, INTENT(IN) :: assert
               TYPE(MPI_Win), INTENT(IN) :: win
               INTEGER, OPTIONAL, INTENT(OUT) :: ierror

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  return  result  of  the  function  and
       Fortran routines in the last argument.

       Before  the  error  value  is  returned,  the current MPI error handler associated with the communication
       object (e.g., communicator, window, file) is called.  If no communication object is associated  with  the
       MPI  call,  then  the call is considered attached to MPI_COMM_SELF and will call the associated MPI error
       handler.  When  MPI_COMM_SELF  is  not  initialized   (i.e.,   before   MPI_Init/MPI_Init_thread,   after
       MPI_Finalize,  or  when using the Sessions Model exclusively) the error raises the initial error handler.
       The initial error handler can be changed by calling MPI_Comm_set_errhandler on MPI_COMM_SELF  when  using
       the  World  model,  or the mpi_initial_errhandler CLI argument to mpiexec or info key to MPI_Comm_spawn/‐
       MPI_Comm_spawn_multiple.  If no other appropriate error handler has been set, then the  MPI_ERRORS_RETURN
       error  handler  is  called for MPI I/O functions and the MPI_ERRORS_ABORT error handler is called for all
       other MPI functions.

       Open MPI includes three predefined error handlers that can be used:

       • MPI_ERRORS_ARE_FATAL Causes the program to abort all connected MPI processes.

       • MPI_ERRORS_ABORT An error handler that can be invoked on a communicator, window, file, or session. When
         called  on  a  communicator,  it  acts  as if MPI_Abort was called on that communicator. If called on a
         window or file, acts as if MPI_Abort was called on a communicator containing the group of processes  in
         the corresponding window or file. If called on a session, aborts only the local process.

       • MPI_ERRORS_RETURN Returns an error code to the application.

       MPI applications can also implement their own error handlers by calling:

       • MPI_Comm_create_errhandler then MPI_Comm_set_errhandler

       • MPI_File_create_errhandler then MPI_File_set_errhandler

       • MPI_Session_create_errhandler then MPI_Session_set_errhandler or at MPI_Session_init

       • MPI_Win_create_errhandler then MPI_Win_set_errhandler

       Note that MPI does not guarantee that an MPI program can continue past an error.

       See the MPI man page for a full list of MPI error codes.

       See the Error Handling section of the MPI-3.1 standard for more information.

       SEE ALSO:

          • MPI_Win_post

          • MPI_Win_complete

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                                  MPI_WIN_START(3)