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<title>Using the GNU Compiler Collection (GCC): Integers implementation</title>
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<a name="Integers-implementation"></a>
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<p>
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Next: <a href="Floating-point-implementation.html#Floating-point-implementation" accesskey="n" rel="next">Floating point implementation</a>, Previous: <a href="Characters-implementation.html#Characters-implementation" accesskey="p" rel="prev">Characters implementation</a>, Up: <a href="C-Implementation.html#C-Implementation" accesskey="u" rel="up">C Implementation</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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<a name="Integers"></a>
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<h3 class="section">4.5 Integers</h3>
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<ul>
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<li> <cite>Any extended integer types that exist in the implementation (C99
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and C11 6.2.5).</cite>
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<p>GCC does not support any extended integer types.
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</p>
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</li><li> <cite>Whether signed integer types are represented using sign and magnitude,
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two’s complement, or one’s complement, and whether the extraordinary value
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is a trap representation or an ordinary value (C99 and C11 6.2.6.2).</cite>
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<p>GCC supports only two’s complement integer types, and all bit patterns
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are ordinary values.
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</p>
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</li><li> <cite>The rank of any extended integer type relative to another extended
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integer type with the same precision (C99 and C11 6.3.1.1).</cite>
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<p>GCC does not support any extended integer types.
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</p>
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</li><li> <cite>The result of, or the signal raised by, converting an integer to a
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signed integer type when the value cannot be represented in an object of
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that type (C90 6.2.1.2, C99 and C11 6.3.1.3).</cite>
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<p>For conversion to a type of width <em>N</em>, the value is reduced
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modulo <em>2^N</em> to be within range of the type; no signal is raised.
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</p>
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</li><li> <cite>The results of some bitwise operations on signed integers (C90
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6.3, C99 and C11 6.5).</cite>
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<p>Bitwise operators act on the representation of the value including
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both the sign and value bits, where the sign bit is considered
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immediately above the highest-value value bit. Signed ‘<samp>>></samp>’ acts
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on negative numbers by sign extension.
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</p>
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<p>As an extension to the C language, GCC does not use the latitude given in
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C99 and C11 only to treat certain aspects of signed ‘<samp><<</samp>’ as undefined.
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However, <samp>-fsanitize=shift</samp> (and <samp>-fsanitize=undefined</samp>) will
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diagnose such cases. They are also diagnosed where constant
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expressions are required.
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</p>
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</li><li> <cite>The sign of the remainder on integer division (C90 6.3.5).</cite>
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<p>GCC always follows the C99 and C11 requirement that the result of division is
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truncated towards zero.
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</p>
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</li></ul>
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<hr>
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<p>
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Next: <a href="Floating-point-implementation.html#Floating-point-implementation" accesskey="n" rel="next">Floating point implementation</a>, Previous: <a href="Characters-implementation.html#Characters-implementation" accesskey="p" rel="prev">Characters implementation</a>, Up: <a href="C-Implementation.html#C-Implementation" accesskey="u" rel="up">C Implementation</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Option-Index.html#Option-Index" title="Index" rel="index">Index</a>]</p>
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