PHP Australia Conference 2015

apc_cas

(PECL apc >= 3.1.1)

apc_casUpdates 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'12) ? 'ok' 'fail'), PHP_EOL;
echo 
'$foobar == 2 ? 1 : 2 = ', (apc_cas('foobar'21) ? 'ok' 'fail'), PHP_EOL;

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

echo 
'$f__bar == 1 ? 2 : 1 = ', (apc_cas('f__bar'12) ? 'ok' 'fail'), PHP_EOL;

apc_store('perfection''xyz');
echo 
'$perfection == 2 ? 1 : 2 = ', (apc_cas('perfection'21) ? '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

See Also

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User Contributed Notes 1 note

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8
Piet Delport
3 years ago
In case anyone is puzzled by the function name, "cas" refers to http://en.wikipedia.org/wiki/Compare-and-swap
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