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이 문서에서는 PHP 중국어 웹사이트 매뉴얼 풀어 주다
(PECL apcu >= 5.1.0)
apcu_entry — Atomically fetch or generate a cache entry
$key
, callable $generator
[, int $ttl
= 0
] )
Atomically attempts to find key
in the cache, if it cannot be found generator
is called, passing key
as the only argument. The return value of the call is then cached with the optionally specified
ttl
, and returned.
Note: When control enters apcu_entry() the lock for the cache is acquired exclusively, it is released when control leaves apcu_entry() : In effect, this turns the body of
generator
into a critical section, disallowing two processes from executing the same code paths concurrently. In addition, it prohibits the concurrent execution of any other APCu functions, since they will acquire the same lock.
The only APCu function that can be called safely by generator
is apcu_entry() .
key
Identity of cache entry
generator
A callable that accepts key
as the only argument and returns the value to cache.
ttl
Time To Live; store var
in the cache for
ttl
seconds. After the
ttl
has passed, the stored variable will be
expunged from the cache (on the next request). If no ttl
is supplied (or if the ttl
is
0), the value will persist until it is removed from
the cache manually, or otherwise fails to exist in the cache (clear,
restart, etc.).
Returns the cached value
Example #1 An apcu_entry() example
<?php
$config = apcu_entry ( "config" , function( $key ) {
return [
"fruit" => apcu_entry ( "config.fruit" , function( $key ){
return [
"apples" ,
"pears"
];
}),
"people" => apcu_entry ( "config.people" , function( $key ){
return [
"bob" ,
"joe" ,
"niki"
];
})
];
});
var_dump ( $config );
?>
以上例程会输出:
array(2) { ["fruit"]=> array(2) { [0]=> string(6) "apples" [1]=> string(5) "pears" } ["people"]=> array(3) { [0]=> string(3) "bob" [1]=> string(3) "joe" [2]=> string(4) "niki" } }