apcu_cas

(PECL apcu >= 4.0.0)

apcu_cas — Updates an old value with a new value

Description

apcu_cas(string $key, int $old, int $new): bool

apcu_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 apcu_cas() example

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

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

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

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

echo '$foobar = ', apcu_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 1 note

down

-2

Anonymous ¶

6 years ago


The output in the example says:

$f__bar == 1 ? 2 : 1 = fail

but in reality it should be:

$f__bar == 1 ? 2 : 1 =  ok 

the first time the code is ran as the cache is empty and apcu_cas allows the key to be inserted.

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