View file File name : Type-Example.html Content :<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <!-- Created by GNU Texinfo 6.8, https://www.gnu.org/software/texinfo/ --> <head> <meta http-equiv="Content-Type" content="text/html; charset=utf-8"> <!-- This manual is for libffi, a portable foreign function interface library. Copyright (C) 2008-2019, 2021 Anthony Green and Red Hat, Inc. Permission is hereby granted, free of charge, to any person obtaining a copy of this software and associated documentation files (the "Software"), to deal in the Software without restriction, including without limitation the rights to use, copy, modify, merge, publish, distribute, sublicense, and/or sell copies of the Software, and to permit persons to whom the Software is furnished to do so, subject to the following conditions: The above copyright notice and this permission notice shall be included in all copies or substantial portions of the Software. THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. --> <title>Type Example (libffi: the portable foreign function interface library)</title> <meta name="description" content="Type Example (libffi: the portable foreign function interface library)"> <meta name="keywords" content="Type Example (libffi: the portable foreign function interface library)"> <meta name="resource-type" content="document"> <meta name="distribution" content="global"> <meta name="Generator" content="makeinfo"> <meta name="viewport" content="width=device-width,initial-scale=1"> <link href="index.html" rel="start" title="Top"> <link href="Index.html" rel="index" title="Index"> <link href="Types.html" rel="up" title="Types"> <link href="Complex.html" rel="next" title="Complex"> <link href="Arrays-Unions-Enums.html" rel="prev" title="Arrays Unions Enums"> <style type="text/css"> <!-- a.copiable-anchor {visibility: hidden; text-decoration: none; line-height: 0em} a.summary-letter {text-decoration: none} blockquote.indentedblock {margin-right: 0em} div.display {margin-left: 3.2em} div.example {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} span.nolinebreak {white-space: nowrap} span.roman {font-family: initial; font-weight: normal} span.sansserif {font-family: sans-serif; font-weight: normal} span:hover a.copiable-anchor {visibility: visible} ul.no-bullet {list-style: none} --> </style> </head> <body lang="en"> <div class="subsection" id="Type-Example"> <div class="header"> <p> Next: <a href="Complex.html" accesskey="n" rel="next">Complex Types</a>, Previous: <a href="Arrays-Unions-Enums.html" accesskey="p" rel="prev">Arrays, Unions, and Enumerations</a>, Up: <a href="Types.html" accesskey="u" rel="up">Types</a> [<a href="Index.html" title="Index" rel="index">Index</a>]</p> </div> <hr> <span id="Type-Example-1"></span><h4 class="subsection">2.3.5 Type Example</h4> <p>The following example initializes a <code>ffi_type</code> object representing the <code>tm</code> struct from Linux’s <samp>time.h</samp>. </p> <p>Here is how the struct is defined: </p> <div class="example"> <pre class="example">struct tm { int tm_sec; int tm_min; int tm_hour; int tm_mday; int tm_mon; int tm_year; int tm_wday; int tm_yday; int tm_isdst; /* Those are for future use. */ long int __tm_gmtoff__; __const char *__tm_zone__; }; </pre></div> <p>Here is the corresponding code to describe this struct to <code>libffi</code>: </p> <div class="example"> <pre class="example"> { ffi_type tm_type; ffi_type *tm_type_elements[12]; int i; tm_type.size = tm_type.alignment = 0; tm_type.type = FFI_TYPE_STRUCT; tm_type.elements = &tm_type_elements; for (i = 0; i < 9; i++) tm_type_elements[i] = &ffi_type_sint; tm_type_elements[9] = &ffi_type_slong; tm_type_elements[10] = &ffi_type_pointer; tm_type_elements[11] = NULL; /* tm_type can now be used to represent tm argument types and return types for ffi_prep_cif() */ } </pre></div> </div> </body> </html>