/usr/share/doc/libffi6/html/Introduction.html is in libffi-dev 3.2.1-8.
This file is owned by root:root, with mode 0o644.
The actual contents of the file can be viewed below.
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 | <!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>Introduction (libffi)</title>
<meta name="description" content="Introduction (libffi)">
<meta name="keywords" content="Introduction (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="index.html#Top" rel="up" title="Top">
<link href="Using-libffi.html#Using-libffi" rel="next" title="Using libffi">
<link href="index.html#Top" rel="prev" title="Top">
<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="Introduction"></a>
<div class="header">
<p>
Next: <a href="Using-libffi.html#Using-libffi" accesskey="n" rel="next">Using libffi</a>, Previous: <a href="index.html#Top" accesskey="p" rel="prev">Top</a>, Up: <a href="index.html#Top" accesskey="u" rel="up">Top</a> [<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<a name="What-is-libffi_003f"></a>
<h2 class="chapter">1 What is libffi?</h2>
<p>Compilers for high level languages generate code that follow certain
conventions. These conventions are necessary, in part, for separate
compilation to work. One such convention is the <em>calling
convention</em>. The calling convention is a set of assumptions made by
the compiler about where function arguments will be found on entry to
a function. A calling convention also specifies where the return
value for a function is found. The calling convention is also
sometimes called the <em>ABI</em> or <em>Application Binary Interface</em>.
<a name="index-calling-convention"></a>
<a name="index-ABI"></a>
<a name="index-Application-Binary-Interface"></a>
</p>
<p>Some programs may not know at the time of compilation what arguments
are to be passed to a function. For instance, an interpreter may be
told at run-time about the number and types of arguments used to call
a given function. ‘<samp>Libffi</samp>’ can be used in such programs to
provide a bridge from the interpreter program to compiled code.
</p>
<p>The ‘<samp>libffi</samp>’ library provides a portable, high level programming
interface to various calling conventions. This allows a programmer to
call any function specified by a call interface description at run
time.
</p>
<p><acronym>FFI</acronym> stands for Foreign Function Interface. A foreign
function interface is the popular name for the interface that allows
code written in one language to call code written in another language.
The ‘<samp>libffi</samp>’ library really only provides the lowest, machine
dependent layer of a fully featured foreign function interface. A
layer must exist above ‘<samp>libffi</samp>’ that handles type conversions for
values passed between the two languages.
<a name="index-FFI"></a>
<a name="index-Foreign-Function-Interface"></a>
</p>
</body>
</html>
|