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    2 => '减小元素的值',
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?>
<div id="memcache.decrement" class="refentry">
 <div class="refnamediv">
  <h1 class="refname">Memcache::decrement</h1>
  <h1 class="refname">memcache_decrement</h1>
  <p class="verinfo">(PECL memcache &gt;= 0.2.0)</p><p class="refpurpose"><span class="refname">Memcache::decrement</span> -- <span class="refname">memcache_decrement</span> &mdash; <span class="dc-title">减小元素的值</span></p>

 </div>

 <div class="refsect1 description" id="refsect1-memcache.decrement-description">
  <h3 class="title">说明</h3>
  <div class="methodsynopsis dc-description">
   <span class="methodname"><strong>Memcache::decrement</strong></span>(<span class="methodparam"><span class="type"><a href="language.types.string.php" class="type string">string</a></span> <code class="parameter">$key</code></span>, <span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$value</code><span class="initializer"> = 1</span></span>): <span class="type"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span>|<span class="type"><a href="language.types.singleton.php" class="type false">false</a></span></span></div>

  <div class="methodsynopsis dc-description"><span class="methodname"><strong>memcache_decrement</strong></span>(<span class="methodparam"><span class="type"><a href="class.memcache.php" class="type Memcache">Memcache</a></span> <code class="parameter">$memcache</code></span>, <span class="methodparam"><span class="type"><a href="language.types.string.php" class="type string">string</a></span> <code class="parameter">$key</code></span>, <span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$value</code><span class="initializer"> = 1</span></span>): <span class="type"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span>|<span class="type"><a href="language.types.singleton.php" class="type false">false</a></span></span></div>


  <p class="para rdfs-comment">
   <span class="function"><strong>Memcache::decrement()</strong></span> 将元素的值减小 <code class="parameter">value</code>。类似于
   <span class="function"><a href="memcache.increment.php" class="function">Memcache::increment()</a></span>，首先将元素当前值转换成数值然后减去 <code class="parameter">value</code>。
   <blockquote class="note"><p><strong class="note">注意</strong>: 
    <span class="simpara">
    新的元素的值不会小于 0。
    </span>
   </p></blockquote>
   <blockquote class="note"><p><strong class="note">注意</strong>: 
    <span class="simpara">
    不要将 <span class="function"><strong>Memcache::decrement()</strong></span> 用于已压缩存储的元素，那样做会导致
    <span class="function"><a href="memcache.get.php" class="function">Memcache::get()</a></span> 方法获取值会失败。
    </span>
   </p></blockquote>
   <span class="function"><strong>Memcache::decrement()</strong></span> 在元素不存在时 <em>不会</em> 创建。
  </p>

 </div>


 <div class="refsect1 parameters" id="refsect1-memcache.decrement-parameters">
  <h3 class="title">参数</h3>
  <dl>
   
    <dt><code class="parameter">key</code></dt>
    <dd>
     <span class="simpara">
      要减小值的元素的key。
     </span>
    </dd>
   
   
    <dt><code class="parameter">value</code></dt>
    <dd>
     <span class="simpara">
      <code class="parameter">value</code>参数指要将指定元素的值减小多少。
     </span>
    </dd>
   
  </dl>
 </div>


 <div class="refsect1 returnvalues" id="refsect1-memcache.decrement-returnvalues">
  <h3 class="title">返回值</h3>
  <p class="simpara">
   成功的时候返回元素的新值 或者在失败时返回 <strong><code><a href="reserved.constants.php#constant.false">false</a></code></strong>
  </p>
 </div>


 <div class="refsect1 examples" id="refsect1-memcache.decrement-examples">
  <h3 class="title">示例</h3>
  <div class="example" id="example-1">
   <p><strong>示例 #1 <span class="function"><strong>Memcache::decrement()</strong></span> example</strong></p>
   <div class="example-contents">
<div class="phpcode"><code><span style="color: #000000"><span style="color: #0000BB">&lt;?php<br /><br /></span><span style="color: #FF8000">/* procedural API */<br /></span><span style="color: #0000BB">$memcache_obj </span><span style="color: #007700">= </span><span style="color: #0000BB">memcache_connect</span><span style="color: #007700">(</span><span style="color: #DD0000">'memcache_host'</span><span style="color: #007700">, </span><span style="color: #0000BB">11211</span><span style="color: #007700">);<br /></span><span style="color: #FF8000">/* 将test_item对应的值减小2 */<br /></span><span style="color: #0000BB">$new_value </span><span style="color: #007700">= </span><span style="color: #0000BB">memcache_decrement</span><span style="color: #007700">(</span><span style="color: #0000BB">$memcache_obj</span><span style="color: #007700">, </span><span style="color: #DD0000">'test_item'</span><span style="color: #007700">, </span><span style="color: #0000BB">2</span><span style="color: #007700">);<br /><br /></span><span style="color: #FF8000">/* OO API */<br /></span><span style="color: #0000BB">$memcache_obj </span><span style="color: #007700">= new </span><span style="color: #0000BB">Memcache</span><span style="color: #007700">;<br /></span><span style="color: #0000BB">$memcache_obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">connect</span><span style="color: #007700">(</span><span style="color: #DD0000">'memcache_host'</span><span style="color: #007700">, </span><span style="color: #0000BB">11211</span><span style="color: #007700">);<br /></span><span style="color: #FF8000">/* decrement item by 3 */<br /></span><span style="color: #0000BB">$new_value </span><span style="color: #007700">= </span><span style="color: #0000BB">$memcache_obj</span><span style="color: #007700">-&gt;</span><span style="color: #0000BB">decrement</span><span style="color: #007700">(</span><span style="color: #DD0000">'test_item'</span><span style="color: #007700">, </span><span style="color: #0000BB">3</span><span style="color: #007700">);<br /></span><span style="color: #0000BB">?&gt;</span></span></code></div>
    </div>

   </div>
 </div>


 <div class="refsect1 seealso" id="refsect1-memcache.decrement-seealso">
  <h3 class="title">参见</h3>
  <ul class="simplelist">
   <li><span class="function"><a href="memcache.increment.php" class="function" rel="rdfs-seeAlso">Memcache::increment()</a> - 增加一个元素的值</span></li>
   <li><span class="function"><a href="memcache.replace.php" class="function" rel="rdfs-seeAlso">Memcache::replace()</a> - 替换已经存在的元素的值</span></li>
  </ul>
 </div>


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