The file pointer must be valid, and must point to a file successfully
opened by fopen() or popen().
ftell() gives undefined results for append-only streams
(opened with "a" flag).
Return Values
Returns the position of the file pointer referenced by
handle
; i.e., its offset into the file stream.
If an error occurs, returns FALSE.
Examples
Example #1 ftell() example
<?php
// opens a file and read some data $fp = fopen("/etc/passwd", "r"); $data = fgets($fp, 12);