In case anyone is puzzled by the function name, "cas" refers to http://en.wikipedia.org/wiki/Compare-and-swap
(PECL apc >= 3.1.1)
apc_cas — Updates an old value with a new value
$key
, int $old
, int $new
) : bool
apc_cas() updates an already existing integer value if the
old
parameter matches the currently stored value
with the value of the new
parameter.
key
The key of the value being updated.
old
The old value (the value currently stored).
new
The new value to update to.
Returns TRUE
on success or FALSE
on failure.
Example #1 apc_cas() example
<?php
apc_store('foobar', 2);
echo '$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
In case anyone is puzzled by the function name, "cas" refers to http://en.wikipedia.org/wiki/Compare-and-swap