MPI_File_write_ordered_begin(3)    Open MPI    MPI_File_write_ordered_begin(3)



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, void *buf,
                  int count, MPI_Datatype datatype)

       Fortran Syntax
           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.




1.4.1                            Jan 14, 2010  MPI_File_write_ordered_begin(3)
