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?>
<div id="class.ffi" class="reference">

 <h1 class="title">C 代码和数据的主接口</h1>
 

 <div class="partintro"><p class="verinfo">(PHP 7 &gt;= 7.4.0, PHP 8)</p>


  <div class="section" id="ffi.intro">
   <h2 class="title">简介</h2>
   <p class="simpara">
    通过工厂方法 <span class="methodname"><a href="ffi.cdef.php" class="methodname">FFI::cdef()</a></span>、<span class="methodname"><a href="ffi.load.php" class="methodname">FFI::load()</a></span> 或 <span class="methodname"><a href="ffi.scope.php" class="methodname">FFI::scope()</a></span>
    创建该类的对象。定义的 C 变量作为有效的 FFI 实例属性，定义的 C 函数作为有效的 FFI 实例方法。声明的 C 类型可以用于
    <span class="methodname"><a href="ffi.new.php" class="methodname">FFI::new()</a></span> 和 <span class="methodname"><a href="ffi.type.php" class="methodname">FFI::type()</a></span> 创建新的 C 数据结构。
   </p>
   <p class="simpara">
    FFI 定义解析和共享库加载可能需要较长时间。在 Web 环境中，每个 HTTP 请求都进行这些操作是没有意义的。然而，在 PHP 启动时预加载
    FFI 定义和库，并在需要时实例化 FFI 对象是可能的。header 文件可以使用特殊的 <code class="literal">FFI_SCOPE</code> 定义进行扩展（例如
    <code class="code">#define FFI_SCOPE &quot;foo&quot;</code>），然后在预加载期间由 <span class="methodname"><a href="ffi.load.php" class="methodname">FFI::load()</a></span> 加载。这将创建持久绑定，将通过
    <span class="methodname"><a href="ffi.scope.php" class="methodname">FFI::scope()</a></span> 在所有后续请求中可用。有关详细信息，请参阅<a href="ffi.examples-complete.php" class="link">完整的 PHP/FFI/preloading 示例</a>。
   </p>
   <p class="simpara">
    可以将多个 C header 文件预加载到同一作用域中。
   </p>
  </div>


  <div class="section" id="ffi.synopsis">
   <h2 class="title">类摘要</h2>


   <div class="classsynopsis"><div class="classsynopsisinfo">
    
     <span class="modifier">final</span>
     <span class="modifier">class</span> <strong class="classname"><strong class="classname">FFI</strong></strong>
     {</div>

    <div class="classsynopsisinfo classsynopsisinfo_comment">/* 常量 */</div>
    <div class="fieldsynopsis">
     <span class="modifier">public</span>
     <span class="modifier">const</span>
     <span class="type"><a href="language.types.integer.php" class="type int">int</a></span>
      <var class="fieldsynopsis_varname"><a href="class.ffi.php#ffi.constants.biggest-alignment"><var class="varname">__BIGGEST_ALIGNMENT__</var></a></var>;</div>


    <div class="classsynopsisinfo classsynopsisinfo_comment">/* 方法 */</div>
    <div class="methodsynopsis dc-description">
   <span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.addr.php" class="methodname">addr</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span> <code class="parameter reference">&$ptr</code></span>): <span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.alignof.php" class="methodname">alignof</a></span>(<span class="methodparam"><span class="type"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span>|<span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span></span> <code class="parameter reference">&$ptr</code></span>): <span class="type"><a href="language.types.integer.php" class="type int">int</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.arraytype.php" class="methodname">arrayType</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span> <code class="parameter">$type</code></span>, <span class="methodparam"><span class="type"><a href="language.types.array.php" class="type array">array</a></span> <code class="parameter">$dimensions</code></span>): <span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="methodname"><a href="ffi.cast.php" class="methodname">cast</a></span>(<span class="methodparam"><span class="type"><span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span>|<span class="type"><a href="language.types.string.php" class="type string">string</a></span></span> <code class="parameter">$type</code></span>, <span class="methodparam"><span class="type"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span>|<span class="type"><a href="language.types.integer.php" class="type int">int</a></span>|<span class="type"><a href="language.types.float.php" class="type float">float</a></span>|<span class="type"><a href="language.types.boolean.php" class="type bool">bool</a></span>|<span class="type"><a href="language.types.null.php" class="type null">null</a></span></span> <code class="parameter reference">&$ptr</code></span>): <span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.cdef.php" class="methodname">cdef</a></span>(<span class="methodparam"><span class="type"><a href="language.types.string.php" class="type string">string</a></span> <code class="parameter">$code</code><span class="initializer"> = &quot;&quot;</span></span>, <span class="methodparam"><span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="language.types.string.php" class="type string">string</a></span></span> <code class="parameter">$lib</code><span class="initializer"> = <strong><code><a href="reserved.constants.php#constant.null">null</a></code></strong></span></span>): <span class="type"><a href="class.ffi.php" class="type FFI">FFI</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.free.php" class="methodname">free</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span> <code class="parameter reference">&$ptr</code></span>): <span class="type"><a href="language.types.void.php" class="type void">void</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.isnull.php" class="methodname">isNull</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span> <code class="parameter reference">&$ptr</code></span>): <span class="type"><a href="language.types.boolean.php" class="type bool">bool</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.load.php" class="methodname">load</a></span>(<span class="methodparam"><span class="type"><a href="language.types.string.php" class="type string">string</a></span> <code class="parameter">$filename</code></span>): <span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="class.ffi.php" class="type FFI">FFI</a></span></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.memcmp.php" class="methodname">memcmp</a></span>(<span class="methodparam"><span class="type"><span class="type"><a href="language.types.string.php" class="type string">string</a></span>|<span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span></span> <code class="parameter reference">&$ptr1</code></span>, <span class="methodparam"><span class="type"><span class="type"><a href="language.types.string.php" class="type string">string</a></span>|<span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span></span> <code class="parameter reference">&$ptr2</code></span>, <span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$size</code></span>): <span class="type"><a href="language.types.integer.php" class="type int">int</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.memcpy.php" class="methodname">memcpy</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span> <code class="parameter reference">&$to</code></span>, <span class="methodparam"><span class="type"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span>|<span class="type"><a href="language.types.string.php" class="type string">string</a></span></span> <code class="parameter reference">&$from</code></span>, <span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$size</code></span>): <span class="type"><a href="language.types.void.php" class="type void">void</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.memset.php" class="methodname">memset</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span> <code class="parameter reference">&$ptr</code></span>, <span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$value</code></span>, <span class="methodparam"><span class="type"><a href="language.types.integer.php" class="type int">int</a></span> <code class="parameter">$size</code></span>): <span class="type"><a href="language.types.void.php" class="type void">void</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="methodname"><a href="ffi.new.php" class="methodname">new</a></span>(<span class="methodparam"><span class="type"><span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span>|<span class="type"><a href="language.types.string.php" class="type string">string</a></span></span> <code class="parameter">$type</code></span>, <span class="methodparam"><span class="type"><a href="language.types.boolean.php" class="type bool">bool</a></span> <code class="parameter">$owned</code><span class="initializer"> = <strong><code><a href="reserved.constants.php#constant.true">true</a></code></strong></span></span>, <span class="methodparam"><span class="type"><a href="language.types.boolean.php" class="type bool">bool</a></span> <code class="parameter">$persistent</code><span class="initializer"> = <strong><code><a href="reserved.constants.php#constant.false">false</a></code></strong></span></span>): <span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.scope.php" class="methodname">scope</a></span>(<span class="methodparam"><span class="type"><a href="language.types.string.php" class="type string">string</a></span> <code class="parameter">$name</code></span>): <span class="type"><a href="class.ffi.php" class="type FFI">FFI</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.sizeof.php" class="methodname">sizeof</a></span>(<span class="methodparam"><span class="type"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span>|<span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span></span> <code class="parameter reference">&$ptr</code></span>): <span class="type"><a href="language.types.integer.php" class="type int">int</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.string.php" class="methodname">string</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span> <code class="parameter reference">&$ptr</code></span>, <span class="methodparam"><span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="language.types.integer.php" class="type int">int</a></span></span> <code class="parameter">$size</code><span class="initializer"> = <strong><code><a href="reserved.constants.php#constant.null">null</a></code></strong></span></span>): <span class="type"><a href="language.types.string.php" class="type string">string</a></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="methodname"><a href="ffi.type.php" class="methodname">type</a></span>(<span class="methodparam"><span class="type"><a href="language.types.string.php" class="type string">string</a></span> <code class="parameter">$type</code></span>): <span class="type"><span class="type"><a href="language.types.null.php" class="type null">?</a></span><span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span></span></div>
<div class="methodsynopsis dc-description"><span class="modifier">public</span> <span class="modifier">static</span> <span class="methodname"><a href="ffi.typeof.php" class="methodname">typeof</a></span>(<span class="methodparam"><span class="type"><a href="class.ffi-cdata.php" class="type FFI\CData">FFI\CData</a></span> <code class="parameter reference">&$ptr</code></span>): <span class="type"><a href="class.ffi-ctype.php" class="type FFI\CType">FFI\CType</a></span></div>

   }</div>


  </div>

  <div class="section" id="class.ffi.constants">
   <h2 class="title">预定义常量</h2>
   <dl>
    
     <dt id="ffi.constants.biggest-alignment"><strong><code><a href="class.ffi.php#ffi.constants.biggest-alignment">FFI::__BIGGEST_ALIGNMENT__</a></code></strong></dt>
     <dd>
      <span class="simpara"/>
     </dd>
    
   </dl>
  </div>
 </div>

 





















































































<h2>目录</h2><ul class="chunklist chunklist_reference"><li><a href="ffi.addr.php">FFI::addr</a> — Creates an unmanaged pointer to C data</li><li><a href="ffi.alignof.php">FFI::alignof</a> — Gets the alignment</li><li><a href="ffi.arraytype.php">FFI::arrayType</a> — Dynamically constructs a new C array type</li><li><a href="ffi.cast.php">FFI::cast</a> — Performs a C type cast</li><li><a href="ffi.cdef.php">FFI::cdef</a> — Creates a new FFI object</li><li><a href="ffi.free.php">FFI::free</a> — Releases an unmanaged data structure</li><li><a href="ffi.isnull.php">FFI::isNull</a> — Checks whether a FFI\CData is a null pointer</li><li><a href="ffi.load.php">FFI::load</a> — Loads C declarations from a C header file</li><li><a href="ffi.memcmp.php">FFI::memcmp</a> — Compares memory areas</li><li><a href="ffi.memcpy.php">FFI::memcpy</a> — Copies one memory area to another</li><li><a href="ffi.memset.php">FFI::memset</a> — Fills a memory area</li><li><a href="ffi.new.php">FFI::new</a> — Creates a C data structure</li><li><a href="ffi.scope.php">FFI::scope</a> — Instantiates an FFI object with C declarations parsed during preloading</li><li><a href="ffi.sizeof.php">FFI::sizeof</a> — Gets the size of C data or types</li><li><a href="ffi.string.php">FFI::string</a> — Creates a PHP string from a memory area</li><li><a href="ffi.type.php">FFI::type</a> — Creates an FFI\CType object from a C declaration</li><li><a href="ffi.typeof.php">FFI::typeof</a> — Gets the FFI\CType of FFI\CData</li></ul>
</div>
<?php manual_footer($setup); ?>