(PECL apc >= 3.1.4)
apc_exists — Checks if APC key exists
Returns TRUE if the key exists, otherwise FALSE Or if an array was passed to keys, then an array is returned that contains all existing keys, or an empty array if none exist.
Example #1 apc_exists() example
<?php
$fruit = 'apple';
$veggie = 'carrot';
apc_store('foo', $fruit);
apc_store('bar', $veggie);
if (apc_exists('foo')) {
echo "Foo exists: ";
echo apc_fetch('foo');
} else {
echo "Foo does not exist";
}
echo PHP_EOL;
if (apc_exists('baz')) {
echo "Baz exists.";
} else {
echo "Baz does not exist";
}
echo PHP_EOL;
$ret = apc_exists(array('foo', 'donotexist', 'bar'));
var_dump($ret);
?>
以上例程的输出类似于：
Foo exists: apple
Baz does not exist
array(2) {
["foo"]=>
bool(true)
["bar"]=>
bool(true)
}