(PHP >= 5.3.0, PECL phar >= 1.0.0)
Phar::offsetExists — determines whether a file exists in the phar
This is an implementation of the ArrayAccess interface allowing direct manipulation of the contents of a Phar archive using array access brackets.
offsetExists() is called whenever isset() is called.
The filename (relative path) to look for in a Phar.
Returns TRUE if the file exists within the phar, or FALSE if not.
Example #1 A Phar::offsetExists() example
<?php
$p = new Phar(dirname(__FILE__) . '/my.phar', 0, 'my.phar');
$p['firstfile.txt'] = 'first file';
$p['secondfile.txt'] = 'second file';
// the next set of lines call offsetExists() indirectly
var_dump(isset($p['firstfile.txt']));
var_dump(isset($p['nothere.txt']));
?>
以上例程会输出：
bool(true) bool(false)