SYNTAX

   C Syntax
          #include <mpi.h>

          int MPI_File_write_ordered_begin(MPI_File fh, const void *buf,
              int count, MPI_Datatype datatype)

   Fortran Syntax
          USE MPI
          ! or the older form: INCLUDE 'mpif.h'

          MPI_FILE_WRITE_ORDERED_BEGIN(FH, BUF, COUNT, DATATYPE, IERROR)
              <type>  BUF(*)
              INTEGER FH, COUNT, DATATYPE, IERROR

   Fortran 2008 Syntax
          USE mpi_f08

          MPI_File_write_ordered_begin(fh, buf, count, datatype, ierror)
              TYPE(MPI_File), INTENT(IN) :: fh
              TYPE(*), DIMENSION(..), INTENT(IN), ASYNCHRONOUS :: buf
              INTEGER, INTENT(IN) :: count
              TYPE(MPI_Datatype), INTENT(IN) :: datatype
              INTEGER, OPTIONAL, INTENT(OUT) :: ierror

INPUT/OUTPUT PARAMETER

       • fh : File handle (handle).

INPUT PARAMETERS

       • buf : Initial address of buffer (choice).

       • count : Number of elements in buffer (integer).

       • datatype : Data type of each buffer element (handle).

OUTPUT PARAMETER

       • ierror : Fortran only: Error status (integer).

DESCRIPTION

       MPI_File_write_ordered_begin  is  the beginning part of a split collective, nonblocking routine that must
       be called by all processes in the communicator group associated with the file handle fh. Each process may
       pass different argument values for the datatype and count arguments. After all  processes  of  the  group
       have  issued  their respective calls, each process attempts to write, into the file associated with fh, a
       total number of count data items having datatype type contained  in  the  user’s  buffer  buf.  For  each
       process,  the  location  in  the  file  at which data is written is the position at which the shared file
       pointer would be after all processes whose ranks within the group are less than that of this process  had
       written their data.

NOTES

       All  the  nonblocking collective routines for data access are “split” into two routines, each with _begin
       or _end as a suffix. These split collective routines are subject  to  the  semantic  rules  described  in
       Section 9.4.5 of the MPI-2 standard.

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.

COPYRIGHT

       2003-2025, The Open MPI Community

                                                  Feb 17, 2025                   MPI_FILE_WRITE_ORDERED_BEGIN(3)