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<h3 class="section">6.22 Arithmetic on <code>void</code>- and Function-Pointers</h3>

<p><a name="index-void-pointers_002c-arithmetic-2307"></a><a name="index-void_002c-size-of-pointer-to-2308"></a><a name="index-function-pointers_002c-arithmetic-2309"></a><a name="index-function_002c-size-of-pointer-to-2310"></a>
In GNU C, addition and subtraction operations are supported on pointers to
<code>void</code> and on pointers to functions.  This is done by treating the
size of a <code>void</code> or of a function as 1.

 <p>A consequence of this is that <code>sizeof</code> is also allowed on <code>void</code>
and on function types, and returns 1.

 <p><a name="index-Wpointer_002darith-2311"></a>The option <samp><span class="option">-Wpointer-arith</span></samp> requests a warning if these extensions
are used.

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