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<title>Type Example (libffi: the portable foreign function interface library)</title>

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<h4 class="subsection" id="Type-Example-1"><span>2.3.5 Type Example<a class="copiable-link" href="#Type-Example-1"> &para;</a></span></h4>

<p>The following example initializes a <code class="code">ffi_type</code> object
representing the <code class="code">tm</code> struct from Linux&rsquo;s <samp class="file">time.h</samp>.
</p>
<p>Here is how the struct is defined:
</p>
<div class="example">
<pre class="example-preformatted">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 class="code">libffi</code>:
</p>
<div class="example">
<pre class="example-preformatted">    {
      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 = &amp;tm_type_elements;

      for (i = 0; i &lt; 9; i++)
          tm_type_elements[i] = &amp;ffi_type_sint;

      tm_type_elements[9] = &amp;ffi_type_slong;
      tm_type_elements[10] = &amp;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>

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