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| 22 | <title>Integer Overflow (GNU C Language Manual)</title>
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| 31 | <link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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| 32 | <link href="Arithmetic.html" rel="up" title="Arithmetic">
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| 33 | <link href="Unsigned-Overflow.html" rel="next" title="Unsigned Overflow">
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| 58 | <span id="Integer-Overflow"></span><div class="header">
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| 59 | <p>
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| 60 | Next: <a href="Mixed-Mode.html" accesskey="n" rel="next">Mixed Mode</a>, Previous: <a href="Integer-Arithmetic.html" accesskey="p" rel="prev">Integer Arithmetic</a>, Up: <a href="Arithmetic.html" accesskey="u" rel="up">Arithmetic</a> [<a href="index.html#SEC_Contents" title="Table of contents" rel="contents">Contents</a>][<a href="Symbol-Index.html" title="Index" rel="index">Index</a>]</p>
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| 61 | </div>
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| 62 | <hr>
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| 63 | <span id="Integer-Overflow-1"></span><h3 class="section">6.3 Integer Overflow</h3>
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| 64 | <span id="index-integer-overflow"></span>
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| 65 | <span id="index-overflow_002c-integer"></span>
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| 66 |
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| 67 | <p>When the mathematical value of an arithmetic operation doesn’t fit in
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| 68 | the range of the data type in use, that’s called <em>overflow</em>.
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| 69 | When it happens in integer arithmetic, it is <em>integer overflow</em>.
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| 70 | </p>
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| 71 | <p>Integer overflow happens only in arithmetic operations. Type conversion
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| 72 | operations, by definition, do not cause overflow, not even when the
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| 73 | result can’t fit in its new type. See <a href="Integer-Conversion.html">Integer Conversion</a>.
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| 74 | </p>
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| 75 | <p>Signed numbers use two’s-complement representation, in which the most
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| 76 | negative number lacks a positive counterpart (see <a href="Integers-in-Depth.html">Integers in Depth</a>). Thus, the unary ‘<samp>-</samp>’ operator on a signed integer can
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| 77 | overflow.
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| 78 | </p>
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| 79 | <table class="menu" border="0" cellspacing="0">
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| 80 | <tr><td align="left" valign="top">• <a href="Unsigned-Overflow.html" accesskey="1">Unsigned Overflow</a></td><td> </td><td align="left" valign="top">Overlow in unsigned integer arithmetic.
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| 81 | </td></tr>
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| 82 | <tr><td align="left" valign="top">• <a href="Signed-Overflow.html" accesskey="2">Signed Overflow</a></td><td> </td><td align="left" valign="top">Overlow in signed integer arithmetic.
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| 83 | </td></tr>
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| 84 | </table>
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| 85 |
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