Note that rewind($fd) is exactly the same as fseek($fd, 0, SEEK_SET)
rewind() just moves the location inside the file to the beginning, nothing more. Check if your stream is "seekable" before planning to use fseek/rewind.
(PHP 4, PHP 5)
rewind — Rewind the position of a file pointer
Sets the file position indicator for handle to the beginning of the file stream.
If you have opened the file in append ("a" or "a+") mode, any data you write to the file will always be appended, regardless of the file position.
The file pointer must be valid, and must point to a file successfully opened by fopen().
Returns TRUE on success or FALSE on failure.
Example #1 rewind() overwriting example
$handle = fopen('output.txt', 'r+');
fwrite($handle, 'Really long sentence.');
echo fread($handle, filesize('output.txt'));
The above example will output something similar to:
Foolly long sentence.