php-doc-en/reference/ffi/ffi.cdata.xml

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<phpdoc:classref xml:id="class.ffi-cdata" xmlns:phpdoc="http://php.net/ns/phpdoc" xmlns="http://docbook.org/ns/docbook" xmlns:xlink="http://www.w3.org/1999/xlink" xmlns:xi="http://www.w3.org/2001/XInclude">

 <title>C Data Handles</title>
 <titleabbrev>FFI\CData</titleabbrev>

 <partintro>

<!-- {{{ FFI\CData intro -->
  <section xml:id="ffi-cdata.intro">
   &reftitle.intro;
   <para>
    <classname>FFI\CData</classname> objects can be used in a number of ways as a regular

    PHP data:
    <itemizedlist>
     <listitem>
      <simpara>
       C data of scalar types can be read and assigned via the <property>$cdata</property> property, e.g. 
       <code>$x = FFI::new('int'); $x->cdata = 42;</code>
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C struct and union fields can be accessed as regular PHP object property, e.g.
       <code>$cdata->field</code>
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C array elements can be accessed as regular PHP array elements, e.g.
       <code>$cdata[$offset]</code>
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C arrays can be iterated using &foreach; statements.
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C arrays can be used as arguments of <function>count</function>.
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C pointers can be dereferenced as arrays, e.g. <code>$cdata[0]</code>
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C pointers can be compared using regualar comparison operators (<code>&lt;</code>,
       <code>&lt;=</code>, <code>==</code>, <code>!=</code>, <code>&gt;=</code>, <code>&gt;</code>).
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C pointers can be incremented and decremented using regular <code>+</code>/<code>-</code>/
       <code>++</code>/<code>–-</code> operations, e.g. <code>$cdata += 5</code>
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C pointers can be subtracted from another using regular <code>-</code> operations.
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       C pointers to functions can be called as a regular PHP closure, e.g. <code>$cdata()</code>
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       Any C data can be duplicated using the <link linkend="language.oop5.cloning">clone</link>
       operator, e.g. <code>$cdata2 = clone $cdata;</code>
      </simpara>
     </listitem>
     <listitem>
      <simpara>
       Any C data can be visualized using <function>var_dump</function>, <function>print_r</function>, etc.
      </simpara>
     </listitem>
    </itemizedlist>
    <note>
     <simpara>
      Noteable limitations are that <classname>FFI\CData</classname> instances do not support
      <function>isset</function>, <function>empty</function> and <function>unset</function>,
      and that wrapped C structs and unions do not implement <interfacename>Traversable</interfacename>.
     </simpara>
    </note>
   </para>
  </section>
<!-- }}} -->

  <section xml:id="ffi-cdata.synopsis">
   &reftitle.classsynopsis;

<!-- {{{ Synopsis -->
   <classsynopsis>
    <ooclass><classname>FFI\CData</classname></ooclass>

<!-- {{{ Class synopsis -->
    <classsynopsisinfo>
     <ooclass>
      <classname>FFI\CData</classname>
     </ooclass>
    </classsynopsisinfo>
<!-- }}} -->

    <!--
    <classsynopsisinfo role="comment">&Methods;</classsynopsisinfo>
    <xi:include xpointer="xmlns(db=http://docbook.org/ns/docbook) xpointer(id('class.ffi-cdata')/db:refentry/db:refsect1[@role='description']/descendant::db:methodsynopsis[not(@role='procedural')])">
     <xi:fallback />
    </xi:include>
    -->

   </classsynopsis>
<!-- }}} -->

  </section>

 </partintro>

 <!-- &reference.ffi.entities.ffi-cdata; -->

</phpdoc:classref>

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