(PECL memcached >= 0.1.0)
Memcached::increment — 增加数值元素的值
$key,$offset = 1,$initial_value = 0,$expiry = 0
Memcached::increment() 将数值元素增加 offset 大小。如果元素的值不是数值类型，将返回错误。如果
key 不存在，Memcached::increment() 会将元素设置为 initial_value 参数。
key要增加值的元素的 key。
offset要将元素的值增加的大小。
initial_value如果元素不存在，要设置的默认值。
expiry设置元素值的过期时间。
成功时返回元素的新值 或者在失败时返回 false。
示例 #1 Memcached::increment() 示例
<?php
$m = new Memcached();
$m->addServer('localhost', 11211);
$m->set('counter', 0);
$m->increment('counter');
$n = $m->increment('counter', 10);
var_dump($n);
$m->set('counter', 'abc');
$n = $m->increment('counter');
// ^ will fail due to item value not being numeric
var_dump($n);
?>以上示例会输出：
int(11) bool(false)
Spent a long time frustrated with this. If you read the patch notes carefully:- Make increment/decrement initialize value when it is not available (when using binary protocol).If you dont have the opt binary protocol set the arguments for initial value just return an error 38 - INVALID ARGUMENTS. This is not documented.PECL memcached < 0.2.0public int Memcached::increment ( string $key [, int $offset = 1 ] )If it'll save others some head-scratching, the PECL Memcached extension only supports initializing increment (or decrement) values from 2.0.0b2 onwards - i.e. not the version (1.0.2) that comes out of the box with Ubuntu 12.04.// Fix for "Memcached::increment(): Initial value is only supported with binary protocol"$m = new Memcached();$m->addServer('localhost', 11211);// Option 1: Or, add the key first to avoid needing initial value support$m->add($key, $initial_value, $expiry);$m->increment($key, $offset);// Option 2: Use binary protocol to support initial value in increment()$m->setOption(Memcached::OPT_BINARY_PROTOCOL, true);$m->increment($key, $offset, $initial_value, $expiry);Tested on PHP 8.4.8