:ref:`MPI_File_write_ordered_begin` |mdash| Writes a file at a location specified by a shared file pointer; beginning part of a split collective routine (nonblocking).
#include <mpi.h>
int MPI_File_write_ordered_begin(MPI_File fh, const void *buf,
int count, MPI_Datatype datatype)
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
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
fh
: File handle (handle).
buf
: Initial address of buffer (choice).count
: Number of elements in buffer (integer).datatype
: Data type of each buffer element (handle).
ierror
: Fortran only: Error status (integer).
:ref:`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.
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.