/usr/share/doc/libffi6/html/Complex-Type-Example.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 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 | <!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>Complex Type Example (libffi)</title>
<meta name="description" content="Complex Type Example (libffi)">
<meta name="keywords" content="Complex Type Example (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="Multiple-ABIs.html#Multiple-ABIs" rel="next" title="Multiple ABIs">
<link href="Complex.html#Complex" rel="prev" title="Complex">
<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="Complex-Type-Example"></a>
<div class="header">
<p>
Previous: <a href="Complex.html#Complex" accesskey="p" rel="prev">Complex</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="Complex-Type-Example-1"></a>
<h4 class="subsection">2.3.5 Complex Type Example</h4>
<p>This example demonstrates how to use complex types:
</p>
<div class="example">
<pre class="example">#include <stdio.h>
#include <ffi.h>
#include <complex.h>
void complex_fn(_Complex float cf,
_Complex double cd,
_Complex long double cld)
{
printf("cf=%f+%fi\ncd=%f+%fi\ncld=%f+%fi\n",
(float)creal (cf), (float)cimag (cf),
(float)creal (cd), (float)cimag (cd),
(float)creal (cld), (float)cimag (cld));
}
int main()
{
ffi_cif cif;
ffi_type *args[3];
void *values[3];
_Complex float cf;
_Complex double cd;
_Complex long double cld;
/* Initialize the argument info vectors */
args[0] = &ffi_type_complex_float;
args[1] = &ffi_type_complex_double;
args[2] = &ffi_type_complex_longdouble;
values[0] = &cf;
values[1] = &cd;
values[2] = &cld;
/* Initialize the cif */
if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 3,
&ffi_type_void, args) == FFI_OK)
{
cf = 1.0 + 20.0 * I;
cd = 300.0 + 4000.0 * I;
cld = 50000.0 + 600000.0 * I;
/* Call the function */
ffi_call(&cif, (void (*)(void))complex_fn, 0, values);
}
return 0;
}
</pre></div>
<p>This is an example for defining a custom complex type descriptor
for compilers that support them:
</p>
<div class="example">
<pre class="example">/*
* This macro can be used to define new complex type descriptors
* in a platform independent way.
*
* name: Name of the new descriptor is ffi_type_complex_<name>.
* type: The C base type of the complex type.
*/
#define FFI_COMPLEX_TYPEDEF(name, type, ffitype) \
static ffi_type *ffi_elements_complex_##name [2] = { \
(ffi_type *)(&ffitype), NULL \
}; \
struct struct_align_complex_##name { \
char c; \
_Complex type x; \
}; \
ffi_type ffi_type_complex_##name = { \
sizeof(_Complex type), \
offsetof(struct struct_align_complex_##name, x), \
FFI_TYPE_COMPLEX, \
(ffi_type **)ffi_elements_complex_##name \
}
/* Define new complex type descriptors using the macro: */
/* ffi_type_complex_sint */
FFI_COMPLEX_TYPEDEF(sint, int, ffi_type_sint);
/* ffi_type_complex_uchar */
FFI_COMPLEX_TYPEDEF(uchar, unsigned char, ffi_type_uint8);
</pre></div>
<p>The new type descriptors can then be used like one of the built-in
type descriptors in the previous example.
</p>
</body>
</html>
|