apc_cas

(PECL apc >= 3.1.1)

apc_cas — Updates an old value with a new value

Description

bool apc_cas ( string $key , int $old , int $new )

apc_cas() updates an already existing integer value if the old parameter matches the currently stored value with the value of the new parameter.

Parameters

key: The key of the value being updated.
old: The old value (the value currently stored).
new: The new value to update to.

Return Values

Returns TRUE on success or FALSE on failure.

Examples

Example #1 apc_cas() example


<?php
apc_store('foobar', 2);
echo '$foobar = 2', PHP_EOL;
echo '$foobar == 1 ? 2 : 1 = ', (apc_cas('foobar', 1, 2) ? 'ok' : 'fail'), PHP_EOL;
echo '$foobar == 2 ? 1 : 2 = ', (apc_cas('foobar', 2, 1) ? 'ok' : 'fail'), PHP_EOL;

echo '$foobar = ', apc_fetch('foobar'), PHP_EOL;

echo '$f__bar == 1 ? 2 : 1 = ', (apc_cas('f__bar', 1, 2) ? 'ok' : 'fail'), PHP_EOL;

apc_store('perfection', 'xyz');
echo '$perfection == 2 ? 1 : 2 = ', (apc_cas('perfection', 2, 1) ? 'ok' : 'epic fail'), PHP_EOL;

echo '$foobar = ', apc_fetch('foobar'), PHP_EOL;
?>

The above example will output something similar to:

$foobar = 2
$foobar == 1 ? 2 : 1 = fail
$foobar == 2 ? 1 : 2 = ok
$foobar = 1
$f__bar == 1 ? 2 : 1 = fail
$perfection == 2 ? 1 : 2 = epic fail
$foobar = 1

User Contributed Notes

Piet Delport

5 years ago


In case anyone is puzzled by the function name, "cas" refers to http://en.wikipedia.org/wiki/Compare-and-swap