106 lines
3.9 KiB
HTML
106 lines
3.9 KiB
HTML
<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
|
|
<html>
|
|
<!--
|
|
This manual is for Libffi, a portable foreign-function interface
|
|
library.
|
|
|
|
Copyright (C) 2008, 2010, 2011 Red Hat, Inc.
|
|
|
|
Permission is granted to copy, distribute and/or modify this document
|
|
under the terms of the GNU General Public License as published by the
|
|
Free Software Foundation; either version 2, or (at your option) any
|
|
later version. A copy of the license is included in the
|
|
section entitled "GNU General Public License".
|
|
-->
|
|
<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->
|
|
<head>
|
|
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
|
|
<title>Structures (libffi)</title>
|
|
|
|
<meta name="description" content="Structures (libffi)">
|
|
<meta name="keywords" content="Structures (libffi)">
|
|
<meta name="resource-type" content="document">
|
|
<meta name="distribution" content="global">
|
|
<meta name="Generator" content="makeinfo">
|
|
<link href="index.html#Top" rel="start" title="Top">
|
|
<link href="Index.html#Index" rel="index" title="Index">
|
|
<link href="Types.html#Types" rel="up" title="Types">
|
|
<link href="Type-Example.html#Type-Example" rel="next" title="Type Example">
|
|
<link href="Primitive-Types.html#Primitive-Types" rel="prev" title="Primitive Types">
|
|
<style type="text/css">
|
|
<!--
|
|
a.summary-letter {text-decoration: none}
|
|
blockquote.indentedblock {margin-right: 0em}
|
|
blockquote.smallindentedblock {margin-right: 0em; font-size: smaller}
|
|
blockquote.smallquotation {font-size: smaller}
|
|
div.display {margin-left: 3.2em}
|
|
div.example {margin-left: 3.2em}
|
|
div.lisp {margin-left: 3.2em}
|
|
div.smalldisplay {margin-left: 3.2em}
|
|
div.smallexample {margin-left: 3.2em}
|
|
div.smalllisp {margin-left: 3.2em}
|
|
kbd {font-style: oblique}
|
|
pre.display {font-family: inherit}
|
|
pre.format {font-family: inherit}
|
|
pre.menu-comment {font-family: serif}
|
|
pre.menu-preformatted {font-family: serif}
|
|
pre.smalldisplay {font-family: inherit; font-size: smaller}
|
|
pre.smallexample {font-size: smaller}
|
|
pre.smallformat {font-family: inherit; font-size: smaller}
|
|
pre.smalllisp {font-size: smaller}
|
|
span.nolinebreak {white-space: nowrap}
|
|
span.roman {font-family: initial; font-weight: normal}
|
|
span.sansserif {font-family: sans-serif; font-weight: normal}
|
|
ul.no-bullet {list-style: none}
|
|
-->
|
|
</style>
|
|
|
|
|
|
</head>
|
|
|
|
<body lang="en">
|
|
<a name="Structures"></a>
|
|
<div class="header">
|
|
<p>
|
|
Next: <a href="Type-Example.html#Type-Example" accesskey="n" rel="next">Type Example</a>, Previous: <a href="Primitive-Types.html#Primitive-Types" accesskey="p" rel="prev">Primitive Types</a>, Up: <a href="Types.html#Types" accesskey="u" rel="up">Types</a> [<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
|
|
</div>
|
|
<hr>
|
|
<a name="Structures-1"></a>
|
|
<h4 class="subsection">2.3.2 Structures</h4>
|
|
|
|
<p>Although ‘<samp>libffi</samp>’ has no special support for unions or
|
|
bit-fields, it is perfectly happy passing structures back and forth.
|
|
You must first describe the structure to ‘<samp>libffi</samp>’ by creating a
|
|
new <code>ffi_type</code> object for it.
|
|
</p>
|
|
<a name="index-ffi_005ftype"></a>
|
|
<dl>
|
|
<dt><a name="index-ffi_005ftype-1"></a>Data type: <strong>ffi_type</strong></dt>
|
|
<dd><p>The <code>ffi_type</code> has the following members:
|
|
</p><dl compact="compact">
|
|
<dt><code>size_t size</code></dt>
|
|
<dd><p>This is set by <code>libffi</code>; you should initialize it to zero.
|
|
</p>
|
|
</dd>
|
|
<dt><code>unsigned short alignment</code></dt>
|
|
<dd><p>This is set by <code>libffi</code>; you should initialize it to zero.
|
|
</p>
|
|
</dd>
|
|
<dt><code>unsigned short type</code></dt>
|
|
<dd><p>For a structure, this should be set to <code>FFI_TYPE_STRUCT</code>.
|
|
</p>
|
|
</dd>
|
|
<dt><code>ffi_type **elements</code></dt>
|
|
<dd><p>This is a ‘<samp>NULL</samp>’-terminated array of pointers to <code>ffi_type</code>
|
|
objects. There is one element per field of the struct.
|
|
</p></dd>
|
|
</dl>
|
|
</dd></dl>
|
|
|
|
|
|
|
|
|
|
|
|
</body>
|
|
</html>
|