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

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.