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Next: <a href="Extended-I_002fO-specifiers.html#Extended-I_002fO-specifiers" accesskey="n" rel="next">Extended I/O specifiers</a>, Previous: <a href="_002eXOR_002e-operator.html#g_t_002eXOR_002e-operator" accesskey="p" rel="prev">.XOR. operator</a>, Up: <a href="Extensions-implemented-in-GNU-Fortran.html#Extensions-implemented-in-GNU-Fortran" accesskey="u" rel="up">Extensions implemented in GNU Fortran</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="Bitwise-logical-operators-1"></a>
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<h4 class="subsection">6.1.29 Bitwise logical operators</h4>
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<a name="index-logical_002c-bitwise"></a>
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<p>With <samp>-fdec</samp>, GNU Fortran relaxes the type constraints on
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logical operators to allow integer operands, and performs the corresponding
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bitwise operation instead. This flag is for compatibility only, and should be
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avoided in new code. Consider:
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</p>
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<div class="smallexample">
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<pre class="smallexample"> INTEGER :: i, j
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i = z'33'
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j = z'cc'
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print *, i .AND. j
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</pre></div>
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<p>In this example, compiled with <samp>-fdec</samp>, GNU Fortran will
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replace the <code>.AND.</code> operation with a call to the intrinsic
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<code><a href="IAND.html#IAND">IAND</a></code> function, yielding the bitwise-and of <code>i</code> and <code>j</code>.
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</p>
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<p>Note that this conversion will occur if at least one operand is of integral
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type. As a result, a logical operand will be converted to an integer when the
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other operand is an integer in a logical operation. In this case,
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<code>.TRUE.</code> is converted to <code>1</code> and <code>.FALSE.</code> to <code>0</code>.
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</p>
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<p>Here is the mapping of logical operator to bitwise intrinsic used with
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<samp>-fdec</samp>:
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</p>
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<table>
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<thead><tr><th width="25%">Operator</th><th width="25%">Intrinsic</th><th width="50%">Bitwise operation</th></tr></thead>
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<tr><td width="25%"><code>.NOT.</code></td><td width="25%"><code><a href="NOT.html#NOT">NOT</a></code></td><td width="50%">complement</td></tr>
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<tr><td width="25%"><code>.AND.</code></td><td width="25%"><code><a href="IAND.html#IAND">IAND</a></code></td><td width="50%">intersection</td></tr>
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<tr><td width="25%"><code>.OR.</code></td><td width="25%"><code><a href="IOR.html#IOR">IOR</a></code></td><td width="50%">union</td></tr>
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<tr><td width="25%"><code>.NEQV.</code></td><td width="25%"><code><a href="IEOR.html#IEOR">IEOR</a></code></td><td width="50%">exclusive or</td></tr>
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<tr><td width="25%"><code>.EQV.</code></td><td width="25%"><code><a href="NOT.html#NOT">NOT</a>(<a href="IEOR.html#IEOR">IEOR</a>)</code></td><td width="50%">complement of exclusive or</td></tr>
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