The function dio_seek() is used to change the file position of the given file descriptor.
The file descriptor returned by dio_open().
The new position.
Specifies how the position pos
should be interpreted:
-
SEEK_SET
(default) - specifies thatpos
is specified from the beginning of the file. -
SEEK_CUR
- Specifies thatpos
is a count of characters from the current file position. This count may be positive or negative. -
SEEK_END
- Specifies thatpos
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.
<?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); ?>
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