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<a name="Integers"></a>
<h3 class="section">4.5 Integers</h3>

<ul>
<li> <cite>Any extended integer types that exist in the implementation (C99
and C11 6.2.5).</cite>

<p>GCC does not support any extended integer types.
</p>
</li><li> <cite>Whether signed integer types are represented using sign and magnitude,
two&rsquo;s complement, or one&rsquo;s complement, and whether the extraordinary value
is a trap representation or an ordinary value (C99 and C11 6.2.6.2).</cite>

<p>GCC supports only two&rsquo;s complement integer types, and all bit patterns
are ordinary values.
</p>
</li><li> <cite>The rank of any extended integer type relative to another extended
integer type with the same precision (C99 and C11 6.3.1.1).</cite>

<p>GCC does not support any extended integer types.
</p>
</li><li> <cite>The result of, or the signal raised by, converting an integer to a
signed integer type when the value cannot be represented in an object of
that type (C90 6.2.1.2, C99 and C11 6.3.1.3).</cite>

<p>For conversion to a type of width <em>N</em>, the value is reduced
modulo <em>2^N</em> to be within range of the type; no signal is raised.
</p>
</li><li> <cite>The results of some bitwise operations on signed integers (C90
6.3, C99 and C11 6.5).</cite>

<p>Bitwise operators act on the representation of the value including
both the sign and value bits, where the sign bit is considered
immediately above the highest-value value bit.  Signed &lsquo;<samp>&gt;&gt;</samp>&rsquo; acts
on negative numbers by sign extension.
</p>
<p>As an extension to the C language, GCC does not use the latitude given in
C99 and C11 only to treat certain aspects of signed &lsquo;<samp>&lt;&lt;</samp>&rsquo; as undefined.
However, <samp>-fsanitize=shift</samp> (and <samp>-fsanitize=undefined</samp>) will
diagnose such cases.  They are also diagnosed where constant
expressions are required.
</p>
</li><li> <cite>The sign of the remainder on integer division (C90 6.3.5).</cite>

<p>GCC always follows the C99 and C11 requirement that the result of division is
truncated towards zero.
</p>
</li></ul>

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