dio_seek

Description

int dio_seek ( resource fd, int pos [, int whence] )

The function dio_seek() is used to change the file position of the file with descriptor fd. The parameter whence specifies how the position pos should be interpreted:

SEEK_SET (default) - specifies that pos is specified from the beginning of the file.
SEEK_CUR - Specifies that pos is a count of characters from the current file position. This count may be positive or negative.
SEEK_END - Specifies that pos is a count of characters from the end of the file. A negative count specifies a position within the current extent of the file; a positive count specifies a position past the current end. If you set the position past the current end, and actually write data, you will extend the file with zeros up to that position.

Example 1. Setting the baud rate on a serial port


<?php

$fd = dio_open('/dev/ttyS0', O_RDWR);

dio_seek($fd, SEEK_SET, 10);
// position is now at 10 characters from the start of the file

dio_seek($fd, SEEK_CUR, -2);
// position is now at 8 characters from the start of the file

dio_seek($fd, SEEK_END, 5);
// position is now at 5 characters from the end of the file

dio_seek($fd, SEEK_END, -10);
// position is now at 10 characters past the end of the file. 
// The 10 characters between the end of the file and the current
// position are filled with zeros.

dio_close($fd);
?>