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- <title>生成一个唯一ID</title>
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- <div class="refnamediv">
- <h1 class="refname">uniqid</h1>
- <p class="verinfo">(PHP 4, PHP 5)</p><p class="refpurpose"><span class="refname">uniqid</span> — <span class="dc-title">生成一个唯一ID</span></p>
- </div>
-
- <div class="refsect1 description" id="refsect1-function.uniqid-description">
- <h3 class="title">说明</h3>
- <div class="methodsynopsis dc-description">
- <span class="type">string</span> <span class="methodname"><strong>uniqid</strong></span>
- ([ <span class="methodparam"><span class="type">string</span> <code class="parameter">$prefix</code><span class="initializer"> = ""</span></span>
- [, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$more_entropy</code><span class="initializer"> = false</span></span>
- ]] )</div>
- <p class="para rdfs-comment">
- 获取一个带前缀、基于当前时间微秒数的唯一ID。
- </p>
- </div>
- <div class="refsect1 parameters" id="refsect1-function.uniqid-parameters">
- <h3 class="title">参数</h3>
- <p class="para">
- <dl>
- <dt>
- <span class="term"><em><code class="parameter">prefix</code></em></span>
- <dd>
- <p class="para">
- 有用的参数。例如:如果在多台主机上可能在同一微秒生成唯一ID。
- </p>
- <p class="para">
- <em><code class="parameter">prefix</code></em>为空,则返回的字符串长度为13。<em><code class="parameter">more_entropy</code></em> 为
- <strong><code>TRUE</code></strong>,则返回的字符串长度为23。
- </p>
- </dd>
- </dt>
- <dt>
- <span class="term"><em><code class="parameter">more_entropy</code></em></span>
- <dd>
- <p class="para">
- 如果设置为 <strong><code>TRUE</code></strong>, <span class="function"><strong>uniqid()</strong></span> 会在返回的字符串结尾增加额外的煽(使用combined linear congruential generator)。
- 使得唯一ID更具唯一性。
- </p>
- </dd>
- </dt>
- </dl>
- </p>
- </div>
- <div class="refsect1 returnvalues" id="refsect1-function.uniqid-returnvalues">
- <h3 class="title">返回值</h3>
- <p class="para">
- 返回字符串形式的唯一ID。
- </p>
- </div>
- <div class="refsect1 examples" id="refsect1-function.uniqid-examples">
- <h3 class="title">范例</h3>
- <p class="para">
- <div class="example" id="example-3579">
- <p><strong>Example #1 <span class="function"><strong>uniqid()</strong></span> 例子</strong></p>
- <div class="example-contents">
- <div class="phpcode"><code><span style="color: #000000">
- <span style="color: #0000BB"><?php<br /></span><span style="color: #FF8000">/* A uniqid, like: 4b3403665fea6 */<br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"uniqid(): %s\r\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">uniqid</span><span style="color: #007700">());<br /><br /></span><span style="color: #FF8000">/* We can also prefix the uniqid, this the same as <br /> * doing:<br /> *<br /> * $uniqid = $prefix . uniqid();<br /> * $uniqid = uniqid($prefix);<br /> */<br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"uniqid('php_'): %s\r\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">uniqid</span><span style="color: #007700">(</span><span style="color: #DD0000">'php_'</span><span style="color: #007700">));<br /><br /></span><span style="color: #FF8000">/* We can also activate the more_entropy parameter, which is <br /> * required on some systems, like Cygwin. This makes uniqid()<br /> * produce a value like: 4b340550242239.64159797<br /> */<br /></span><span style="color: #0000BB">printf</span><span style="color: #007700">(</span><span style="color: #DD0000">"uniqid('', true): %s\r\n"</span><span style="color: #007700">, </span><span style="color: #0000BB">uniqid</span><span style="color: #007700">(</span><span style="color: #DD0000">''</span><span style="color: #007700">, </span><span style="color: #0000BB">true</span><span style="color: #007700">));<br /></span><span style="color: #0000BB">?></span>
- </span>
- </code></div>
- </div>
- </div>
- </p>
- </div>
- <div class="refsect1 changelog" id="refsect1-function.uniqid-changelog">
- <h3 class="title">更新日志</h3>
- <p class="para">
- <table class="doctable informaltable">
-
- <thead>
- <tr>
- <th>版本</th>
- <th>说明</th>
- </tr>
- </thead>
- <tbody class="tbody">
- <tr>
- <td>5.0.0</td>
- <td>
- <em><code class="parameter">prefix</code></em> 参数设为可选。
- </td>
- </tr>
- <tr>
- <td>4.3.1</td>
- <td>
- <em><code class="parameter">prefix</code></em> 参数的长度限制提升到114个字符。
- </td>
- </tr>
- </tbody>
-
- </table>
- </p>
- </div>
- <div class="refsect1 notes" id="refsect1-function.uniqid-notes">
- <h3 class="title">注释</h3>
- <blockquote class="note"><p><strong class="note">Note</strong>:
- <p class="para">
- 在Cygwin环境下,为了使此函数能够工作,<em><code class="parameter">more_entropy</code></em> 必须设置为 <strong><code>TRUE</code></strong>。
- </p>
- </p></blockquote>
- </div>
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