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| 22 | <title>Argument Promotions (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="Type-Conversions.html" rel="up" title="Type Conversions">
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| 33 | <link href="Operand-Promotions.html" rel="next" title="Operand Promotions">
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| 57 | <body lang="en">
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| 58 | <span id="Argument-Promotions"></span><div class="header">
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| 59 | <p>
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| 60 | Next: <a href="Operand-Promotions.html" accesskey="n" rel="next">Operand Promotions</a>, Previous: <a href="Assignment-Type-Conversions.html" accesskey="p" rel="prev">Assignment Type Conversions</a>, Up: <a href="Type-Conversions.html" accesskey="u" rel="up">Type Conversions</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="Argument-Promotions-1"></span><h3 class="section">24.3 Argument Promotions</h3>
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| 64 | <span id="index-argument-promotions"></span>
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| 65 | <span id="index-promotion-of-arguments"></span>
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| 66 |
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| 67 | <p>When a function’s definition or declaration does not specify the type
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| 68 | of an argument, that argument is passed without conversion in whatever
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| 69 | type it has, with these exceptions:
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| 70 | </p>
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| 71 | <ul>
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| 72 | <li> Some narrow numeric values are <em>promoted</em> to a wider type. If the
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| 73 | expression is a narrow integer, such as <code>char</code> or <code>short</code>,
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| 74 | the call converts it automatically to <code>int</code> (see <a href="Integer-Types.html">Integer Types</a>).<a id="DOCF8" href="#FOOT8"><sup>8</sup></a>
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| 75 |
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| 76 | <p>In this example, the expression <code>c</code> is passed as an <code>int</code>:
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| 77 | </p>
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| 78 | <div class="example">
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| 79 | <pre class="example">char c = '$';
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| 80 |
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| 81 | printf ("Character c is '%c'\n", c);
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| 82 | </pre></div>
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| 83 |
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| 84 | </li><li> If the expression
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| 85 | has type <code>float</code>, the call converts it automatically to
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| 86 | <code>double</code>.
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| 87 |
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| 88 | </li><li> An array as argument is converted to a pointer to its zeroth element.
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| 89 |
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| 90 | </li><li> A function name as argument is converted to a pointer to that function.
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| 91 | </li></ul>
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| 92 |
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| 93 | <div class="footnote">
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| 94 | <hr>
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| 95 | <h4 class="footnotes-heading">Footnotes</h4>
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| 96 |
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| 97 | <h5><a id="FOOT8" href="#DOCF8">(8)</a></h3>
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| 98 | <p>On an embedded controller where <code>char</code>
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| 99 | or <code>short</code> is the same width as <code>int</code>, <code>unsigned char</code>
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| 100 | or <code>unsigned short</code> promotes to <code>unsigned int</code>, but that
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| 101 | never occurs in GNU C on real computers.</p>
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| 102 | </div>
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| 103 |
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| 104 |
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| 105 |
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