Availability:C-language interface function
int Sseek(IOSTREAM
*s, long pos, int whence)
int Sseek64(IOSTREAM
*s, int64_t pos, int whence)Reposition the file pointer in the object associated to s,
returning 0 on success and -1 otherwise. If the stream is buffered and
position information is maintained these functions readjust the buffer
information if possible. Otherwise they call Sseek64_function()
or Sseek_function() as a fallback iff pos can be
represented as a C long. Whence is one of SIO_SEEK_SET,
SIO_SEEK_CUR or SIO_SEEK_END, seeking relative
to the start, current position or end.