PHP 手册
上一页 |  | 下一页

# apc_add

(no version information, might be only in CVS)

apc_add -- Cache a variable in the data store (only if it's not stored)

## 说明

bool apc_add ( string key, mixed var [, int ttl] )

> 注意: Unlike many other mechanisms in PHP, variables stored using apc_add() will persist between requests (until the value is removed from the cache).

## 参数

`key`

  Store the variable using this name. `key`s are cache-unique, so attempting to use apc_add() to store data with a key that already exists will not overwrite the existing data, and will instead return `FALSE`. (This is the only difference between apc_add() and apc_store().)

`var`

  The variable to store

`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.).

## 返回值

如果成功则返回 `TRUE`，失败则返回 `FALSE`。

## 范例

例 1. A apc_add() example

`<?php $bar = 'BAR'; apc_add('foo', $bar); var_dump(apc_fetch('foo')); echo "\n"; $bar = 'NEVER GETS SET'; apc_add('foo', $bar); var_dump(apc_fetch('foo')); echo "\n"; ?>`

上例将输出：

    string(3) "BAR"
    string(3) "BAR"

## 参见

apc_store()
apc_fetch()
apc_delete()

上一页 | 起始页 | 下一页
APC 可选 PHP 缓存 | 上一级 | apc_cache_info