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)
- 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).
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.