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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).
C Syntax
#include <mpi.h>
int MPI_File_write_ordered_begin(MPI_File fh, const void *buf,
int count, MPI_Datatype datatype)
INCLUDE ’mpif.h’
MPI_FILE_WRITE_ORDERED_BEGIN(FH, BUF, COUNT, DATATYPE, IERROR)
<type> BUF(*)
INTEGER FH, COUNT, DATATYPE, IERROR
#include <mpi.h>
void MPI::File::Write_ordered_begin(const void* buf, int count,
const MPI::Datatype& datatype)
- 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).
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.
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.
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