NAME

       MPI_File_write_ordered_begin  - Writes a file at a location specified by a shared file pointer; beginning
       part of a split collective routine (nonblocking).

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

C++ Syntax

       #include <mpi.h>
       void MPI::File::Write_ordered_begin(const void* buf, int count,
            const MPI::Datatype& datatype)

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  value  of  the  function  and  Fortran
       routines in the last argument. C++ functions 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. For MPI I/O function errors,
       the default  error  handler  is  set  to  MPI_ERRORS_RETURN.  The  error  handler  may  be  changed  with
       MPI_File_set_errhandler; the predefined error handler MPI_ERRORS_ARE_FATAL may be used to make I/O errors
       fatal. Note that MPI does not guarantee that an MPI program can continue past an error.

4.1.6                                             Sep 30, 2023                   MPI_File_write_ordered_begin(3)