(PHP 4 >= 4.2.0, PHP 5 <= 5.0.5, PHP 7)
dio_seek — Seeks to pos on fd from whence
$fd
, int $pos
[, int $whence = SEEK_SET
] )The function dio_seek() is used to change the file position of the given file descriptor.
fdThe file descriptor returned by dio_open().
posThe new position.
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 Positioning in a file
<?php
$fd = dio_open('/dev/ttyS0', O_RDWR);
dio_seek($fd, 10, SEEK_SET);
// position is now at 10 characters from the start of the file
dio_seek($fd, -2, SEEK_CUR);
// position is now at 8 characters from the start of the file
dio_seek($fd, -5, SEEK_END);
// position is now at 5 characters from the end of the file
dio_seek($fd, 10, SEEK_END);
// position is now at 10 characters past the end of the file.
// The 10 characters between the end of the file and the current
// position are filled with zeros.
dio_close($fd);
?>