mirror of
https://github.com/fofolee/uTools-Manuals.git
synced 2025-06-18 05:26:57 +08:00
124 lines
3.9 KiB
HTML
124 lines
3.9 KiB
HTML
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
||
<html>
|
||
<head>
|
||
<meta http-equiv="content-type" content="text/html; charset=UTF-8">
|
||
<title>Acquire a semaphore</title>
|
||
</head>
|
||
<body class="docs"><div id="layout">
|
||
<div id="layout-content"><div id="function.sem-acquire" class="refentry">
|
||
<div class="refnamediv">
|
||
<h1 class="refname">sem_acquire</h1>
|
||
<p class="verinfo">(PHP 4, PHP 5, PHP 7)</p><p class="refpurpose"><span class="refname">sem_acquire</span> — <span class="dc-title">Acquire a semaphore</span></p>
|
||
|
||
</div>
|
||
|
||
<div class="refsect1 description" id="refsect1-function.sem-acquire-description">
|
||
<h3 class="title">说明</h3>
|
||
<div class="methodsynopsis dc-description">
|
||
<span class="methodname"><strong>sem_acquire</strong></span>
|
||
( <span class="methodparam"><span class="type">resource</span> <code class="parameter">$sem_identifier</code></span>
|
||
[, <span class="methodparam"><span class="type">bool</span> <code class="parameter">$nowait</code><span class="initializer"> = <strong><code>FALSE</code></strong></span></span>
|
||
] ) : <span class="type">bool</span></div>
|
||
|
||
<p class="para rdfs-comment">
|
||
<span class="function"><strong>sem_acquire()</strong></span> by default blocks (if necessary) until the
|
||
semaphore can be acquired. A process attempting to acquire a semaphore which
|
||
it has already acquired will block forever if acquiring the semaphore would
|
||
cause its maximum number of semaphore to be exceeded.
|
||
</p>
|
||
<p class="para">
|
||
After processing a request, any semaphores acquired by the process but not
|
||
explicitly released will be released automatically and a warning will be
|
||
generated.
|
||
</p>
|
||
</div>
|
||
|
||
|
||
<div class="refsect1 parameters" id="refsect1-function.sem-acquire-parameters">
|
||
<h3 class="title">参数</h3>
|
||
<p class="para">
|
||
<dl>
|
||
|
||
|
||
<dt>
|
||
<code class="parameter">sem_identifier</code></dt>
|
||
|
||
<dd>
|
||
|
||
<p class="para">
|
||
<code class="parameter">sem_identifier</code> is a semaphore resource,
|
||
obtained from <span class="function"><a href="sem_get.html" class="function">sem_get()</a></span>.
|
||
</p>
|
||
</dd>
|
||
|
||
|
||
|
||
<dt>
|
||
<code class="parameter">nowait</code></dt>
|
||
|
||
<dd>
|
||
|
||
<p class="para">
|
||
Specifies if the process shouldn't wait for the semaphore to be acquired.
|
||
If set to <em>true</em>, the call will return
|
||
<em>false</em> immediately if a semaphore cannot be immediately
|
||
acquired.
|
||
</p>
|
||
</dd>
|
||
|
||
|
||
</dl>
|
||
|
||
</p>
|
||
</div>
|
||
|
||
|
||
<div class="refsect1 returnvalues" id="refsect1-function.sem-acquire-returnvalues">
|
||
<h3 class="title">返回值</h3>
|
||
<p class="para">
|
||
成功时返回 <strong><code>TRUE</code></strong>， 或者在失败时返回 <strong><code>FALSE</code></strong>。
|
||
</p>
|
||
</div>
|
||
|
||
|
||
<div class="refsect1 changelog" id="refsect1-function.sem-acquire-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>5.6.1</td>
|
||
<td>
|
||
The <code class="parameter">$nowait</code> parameter was added.
|
||
</td>
|
||
</tr>
|
||
|
||
</tbody>
|
||
|
||
</table>
|
||
|
||
</p>
|
||
</div>
|
||
|
||
|
||
<div class="refsect1 seealso" id="refsect1-function.sem-acquire-seealso">
|
||
<h3 class="title">参见</h3>
|
||
<p class="para">
|
||
<ul class="simplelist">
|
||
<li class="member"><span class="function"><a href="sem_get.html" class="function" rel="rdfs-seeAlso">sem_get()</a> - Get a semaphore id</span></li>
|
||
<li class="member"><span class="function"><a href="sem_release.html" class="function" rel="rdfs-seeAlso">sem_release()</a> - Release a semaphore</span></li>
|
||
</ul>
|
||
</p>
|
||
</div>
|
||
|
||
|
||
</div></div></div></body></html> |