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copied!<p>Several answers here state that if an <code>int</code> has a width of 16 bits, <code>0xFFFF</code> is negative. This is not true. <code>0xFFFF</code> is never negative.</p> <p>A hexadecimal literal is represented by the first of the following types that is large enough to contain it: <code>int</code>, <code>unsigned int</code>, <code>long</code>, and <code>unsigned long</code>.</p> <p>If <code>int</code> has a width of 16 bits, then <code>0xFFFF</code> is larger than the maximum value representable by an <code>int</code>. Thus, <code>0xFFFF</code> is of type <code>unsigned int</code>, which is guaranteed to be large enough to represent <code>0xFFFF</code>.</p> <p>When the usual arithmetic conversions are performed for evaluation of the <code>&</code>, the <code>unsigned int</code> is converted to a <code>long</code>. The conversion of a 16-bit <code>unsigned int</code> to <code>long</code> is well-defined because every value representable by a 16-bit <code>unsigned int</code> is also representable by a 32-bit <code>long</code>. </p> <p>There's no sign extension needed because the initial type is not signed, and the result of using <code>0xFFFF</code> is the same as the result of using <code>0xFFFFL</code>.</p> <p>Alternatively, if <code>int</code> is wider than 16 bits, then <code>0xFFFF</code> is of type <code>int</code>. It is a signed, but positive, number. In this case both operands are signed, and <code>long</code> has the greater conversion rank, so the <code>int</code> is again promoted to <code>long</code> by the usual arithmetic conversions.</p> <hr> <p>As others have said, you should avoid performing bitwise operations on signed operands because the numeric result is dependent upon how signedness is represented.</p> <p>Aside from that, there's nothing particularly wrong with this code. I would argue that it's a style concern that <code>value</code> is not initialized when it is declared, but that's probably a nit-pick level comment and depends upon the contents of the <code>//some stuff</code> section that was omitted. </p> <p>It's probably also preferable to use a fixed-width integer type (like <code>uint32_t</code>) instead of <code>long</code> for greater portability, but really that too depends on the code you are writing and what your basic assumptions are.</p>

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