132 lines
4.1 KiB
HTML
132 lines
4.1 KiB
HTML
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<!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd">
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<html>
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<!--
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This manual is for Libffi, a portable foreign-function interface
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library.
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Copyright (C) 2008, 2010, 2011 Red Hat, Inc.
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Permission is granted to copy, distribute and/or modify this document
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under the terms of the GNU General Public License as published by the
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Free Software Foundation; either version 2, or (at your option) any
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later version. A copy of the license is included in the
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section entitled "GNU General Public License".
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-->
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<!-- Created by GNU Texinfo 6.5, http://www.gnu.org/software/texinfo/ -->
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<head>
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<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
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<title>Closure Example (libffi)</title>
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<meta name="description" content="Closure Example (libffi)">
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<meta name="keywords" content="Closure Example (libffi)">
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<meta name="Generator" content="makeinfo">
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<link href="index.html#Top" rel="start" title="Top">
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<link href="Index.html#Index" rel="index" title="Index">
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<link href="Using-libffi.html#Using-libffi" rel="up" title="Using libffi">
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<link href="Missing-Features.html#Missing-Features" rel="next" title="Missing Features">
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<link href="The-Closure-API.html#The-Closure-API" rel="prev" title="The Closure API">
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</head>
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<body lang="en">
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<a name="Closure-Example"></a>
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<div class="header">
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<p>
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Previous: <a href="The-Closure-API.html#The-Closure-API" accesskey="p" rel="prev">The Closure API</a>, Up: <a href="Using-libffi.html#Using-libffi" accesskey="u" rel="up">Using libffi</a> [<a href="Index.html#Index" title="Index" rel="index">Index</a>]</p>
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</div>
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<hr>
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<a name="Closure-Example-1"></a>
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<h3 class="section">2.6 Closure Example</h3>
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<p>A trivial example that creates a new <code>puts</code> by binding
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<code>fputs</code> with <code>stdout</code>.
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</p>
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<div class="example">
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<pre class="example">#include <stdio.h>
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#include <ffi.h>
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/* Acts like puts with the file given at time of enclosure. */
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void puts_binding(ffi_cif *cif, void *ret, void* args[],
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void *stream)
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{
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*(ffi_arg *)ret = fputs(*(char **)args[0], (FILE *)stream);
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}
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typedef int (*puts_t)(char *);
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int main()
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{
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ffi_cif cif;
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ffi_type *args[1];
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ffi_closure *closure;
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void *bound_puts;
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int rc;
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/* Allocate closure and bound_puts */
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closure = ffi_closure_alloc(sizeof(ffi_closure), &bound_puts);
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if (closure)
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{
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/* Initialize the argument info vectors */
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args[0] = &ffi_type_pointer;
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/* Initialize the cif */
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if (ffi_prep_cif(&cif, FFI_DEFAULT_ABI, 1,
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&ffi_type_sint, args) == FFI_OK)
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{
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/* Initialize the closure, setting stream to stdout */
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if (ffi_prep_closure_loc(closure, &cif, puts_binding,
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stdout, bound_puts) == FFI_OK)
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{
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rc = ((puts_t)bound_puts)("Hello World!");
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/* rc now holds the result of the call to fputs */
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}
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}
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}
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/* Deallocate both closure, and bound_puts */
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ffi_closure_free(closure);
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return 0;
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}
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</pre></div>
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</body>
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</html>
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