OwlCyberSecurity - MANAGER

Edit File: Closure-Example.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.

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.
 -->

<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>Closure Example (libffi: the portable foreign function interface library)</title>

</head>

<body lang="en">
<span id="Closure-Example"></span><div class="header">
<p>
Next: <a href="Thread-Safety.html" accesskey="n" rel="next">Thread Safety</a>, Previous: <a href="The-Closure-API.html" accesskey="p" rel="prev">The Closure API</a>, Up: <a href="Using-libffi.html" accesskey="u" rel="up">Using libffi</a> &nbsp; [<a href="Index.html" title="Index" rel="index">Index</a>]</p>
</div>
<hr>
<span id="Closure-Example-1"></span><h3 class="section">2.6 Closure Example</h3>

<p>A trivial example that creates a new <code>puts</code> by binding 
<code>fputs</code> with <code>stdout</code>.
</p>
<div class="example">
<pre class="example">#include &lt;stdio.h&gt;
#include &lt;ffi.h&gt;

/* Acts like puts with the file given at time of enclosure. */
void puts_binding(ffi_cif *cif, void *ret, void* args[],
                  void *stream)
{
  *(ffi_arg *)ret = fputs(*(char **)args[0], (FILE *)stream);
}

typedef int (*puts_t)(char *);

int main()
{
  ffi_cif cif;
  ffi_type *args[1];
  ffi_closure *closure;

void *bound_puts;
  int rc;

/* Allocate closure and bound_puts */
  closure = ffi_closure_alloc(sizeof(ffi_closure), &amp;bound_puts);

if (closure)
    {
      /* Initialize the argument info vectors */
      args[0] = &amp;ffi_type_pointer;

/* Initialize the cif */
      if (ffi_prep_cif(&amp;cif, FFI_DEFAULT_ABI, 1,
                       &amp;ffi_type_sint, args) == FFI_OK)
        {
          /* Initialize the closure, setting stream to stdout */
          if (ffi_prep_closure_loc(closure, &amp;cif, puts_binding,
                                   stdout, bound_puts) == FFI_OK)
            {
              rc = ((puts_t)bound_puts)(&quot;Hello World!&quot;);
              /* rc now holds the result of the call to fputs */
            }
        }
    }

/* Deallocate both closure, and bound_puts */
  ffi_closure_free(closure);

return 0;
}

</pre></div>

</body>
</html>