(PHP 4 >= 4.2.0, PHP 5, PHP 7, PHP 8)
session_cache_expire — 返回/设置当前缓存的到期时间
session_cache_expire() 返回
session.cache_expire 的设定值。
请求开始的时候，缓存到期时间会被重置为 180，并且保存在 session.cache_expire 配置项中。 因此，针对每个请求，需要在 session_start() 函数调用之前 调用 session_cache_expire() 来设置缓存到期时间。
value
如果指定 value 且不为 null，就使用
value 的值替换当前缓存到期时间。
注意: 仅在
session.cache_limiter的设置值 不是nocache的时候， 才可以设置value参数。
返回 session.cache_expire 的当前设置值，
以分钟为单位，默认值是 180 （分钟）。如果更改值失败，则返回 false。
| 版本 | 说明 |
|---|---|
| 8.0.0 |
value 现在可以为 null。
|
示例 #1 session_cache_expire() 示例
<?php
/* 设置缓存限制为 “private” */
session_cache_limiter('private');
$cache_limiter = session_cache_limiter();
/* 设置缓存过期时间为 30 分钟 */
session_cache_expire(30);
$cache_expire = session_cache_expire();
/* 开始会话 */
session_start();
echo "The cache limiter is now set to $cache_limiter<br />";
echo "The cached session pages expire after $cache_expire minutes";
?>The manual probably doesn't stress this enough:
** This has nothing to do with lifetime of a session **
Whatever you set this setting to, it won't change how long sessions live on your server.
This only changes HTTP cache expiration time (Expires: and Cache-Control: max-age headers), which advise browser for how long it can keep pages cached in user's cache without having to reload them from the server.Using PHP 8.2
session_start();
$result1 = session_cache_expire( 30 ); // setter, results in Warning: Session cache expiration cannot be changed when a session is active in ...
$result2 = session_cache_expire(); // getter
var_dump( $result1, $result2 ); // prints out: int(180) int(180) [note: 180 is the default value]
Because the session was already started, cache expiration could not be changed (warning message). However, the return value is NOT false, it is still the original, unchanged value!
So I do not know what is considered a failure to change the value as per the documentation (`On failure to change the value, false is returned.`).