Manpages - MPI_File_seek.3

MPI_File_seek - Updates individual file pointers (noncollective).

  #include <mpi.h>
  int MPI_File_seek(MPI_File fh, MPI_Offset offset,
  	int whence)

  USE MPI
  ! or the older form: INCLUDE 'mpif.h'
  MPI_FILE_SEEK(FH, OFFSET, WHENCE, IERROR)
  	INTEGER	FH, WHENCE, IERROR
  	INTEGER(KIND=MPI_OFFSET_KIND)	OFFSET

  USE mpi_f08
  MPI_File_seek(fh, offset, whence, ierror)
  	TYPE(MPI_File), INTENT(IN) :: fh
  	INTEGER(KIND=MPI_OFFSET_KIND), INTENT(IN) :: offset
  	INTEGER, INTENT(IN) :: whence
  	INTEGER, OPTIONAL, INTENT(OUT) :: ierror

  #include <mpi.h>
  void MPI::File::Seek(MPI::Offset offset, int whence)

fh

File handle (handle).

offset

File offset (integer).

whence

Update mode (integer).

IERROR

Fortran only: Error status (integer).

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.

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.

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.