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<title>Using the GNU Compiler Collection (GCC)</title>
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<h3 class="section">Incomplete <code>enum</code> Types</h3>
<p>You can define an <code>enum</code> tag without specifying its possible values.
This results in an incomplete type, much like what you get if you write
<code>struct foo</code> without describing the elements. A later declaration
which does specify the possible values completes the type.
<p>You can't allocate variables or storage using the type while it is
incomplete. However, you can work with pointers to that type.
<p>This extension may not be very useful, but it makes the handling of
<code>enum</code> more consistent with the way <code>struct</code> and <code>union</code>
are handled.
<p>This extension is not supported by GNU C++.
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