NAME¶
MPI_File_seek - Updates individual file pointers (noncollective).
SYNTAX¶
C Syntax
#include <mpi.h>
int MPI_File_seek(MPI_File fh, MPI_Offset offset,
int whence)
Fortran Syntax (see FORTRAN 77 NOTES)¶
INCLUDE 'mpif.h'
MPI_FILE_SEEK( FH, OFFSET, WHENCE, IERROR)
INTEGER FH, WHENCE, IERROR
INTEGER(KIND=MPI_OFFSET_KIND) OFFSET
C++ Syntax¶
#include <mpi.h>
void MPI::File::Seek(MPI::Offset offset, int whence)
- fh
- File handle (handle).
- offset
- File offset (integer).
- whence
- Update mode (integer).
OUTPUT PARAMETER¶
- IERROR
- Fortran only: Error status (integer).
DESCRIPTION¶
MPI_File_seek updates the individual file pointer according to
whence,
which could have the following possible values:
-
o
- MPI_SEEK_SET - The pointer is set to offset.
-
o
- MPI_SEEK_CUR - The pointer is set to the current pointer
position plus offset.
-
o
- MPI_SEEK_END - The pointer is set to the end of the file
plus offset.
The
offset can be negative, which allows seeking backwards. It is
erroneous to seek to a negative position in the file. The end of the file is
defined to be the location of the next elementary data item immediately after
the last accessed data item, even if that location is a hole.
FORTRAN 77 NOTES¶
The MPI standard prescribes portable Fortran syntax for the
OFFSET
argument only for Fortran 90. FORTRAN 77 users may use the non-portable syntax
INTEGER*MPI_OFFSET_KIND OFFSET
where MPI_OFFSET_KIND is a constant defined in mpif.h and gives the length of
the declared integer in bytes.
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.