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| 22 | <title>Wide Character Constants (GNU C Language Manual)</title>
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| 57 | <body lang="en">
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| 58 | <span id="Wide-Character-Constants"></span><div class="header">
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| 59 | <p>
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| 60 | Next: <a href="Wide-String-Constants.html" accesskey="n" rel="next">Wide String Constants</a>, Previous: <a href="Unicode-Character-Codes.html" accesskey="p" rel="prev">Unicode Character Codes</a>, Up: <a href="Constants.html" accesskey="u" rel="up">Constants</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="Wide-Character-Constants-1"></span><h3 class="section">12.10 Wide Character Constants</h3>
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| 64 | <span id="index-wide-character-constants"></span>
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| 65 | <span id="index-constants_002c-wide-character"></span>
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| 66 |
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| 67 | <p>A <em>wide character constant</em> represents characters with more than 8
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| 68 | bits of character code. This is an obscure feature that we need to
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| 69 | document but that you probably won’t ever use. If you’re just
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| 70 | learning C, you may as well skip this section.
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| 71 | </p>
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| 72 | <p>The original C wide character constant looks like ‘<samp>L</samp>’ (upper
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| 73 | case!) followed immediately by an ordinary character constant (with no
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| 74 | intervening space). Its data type is <code>wchar_t</code>, which is an
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| 75 | alias defined in <samp>stddef.h</samp> for one of the standard integer
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| 76 | types. Depending on the platform, it could be 16 bits or 32 bits. If
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| 77 | it is 16 bits, these character constants use the UTF-16 form of
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| 78 | Unicode; if 32 bits, UTF-32.
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| 79 | </p>
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| 80 | <p>There are also Unicode wide character constants which explicitly
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| 81 | specify the width. These constants start with ‘<samp>u</samp>’ or ‘<samp>U</samp>’
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| 82 | instead of ‘<samp>L</samp>’. ‘<samp>u</samp>’ specifies a 16-bit Unicode wide
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| 83 | character constant, and ‘<samp>U</samp>’ a 32-bit Unicode wide character
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| 84 | constant. Their types are, respectively, <code>char16_t</code> and
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| 85 | <code><span class="nolinebreak">char32_t</span></code><!-- /@w -->; they are declared in the header file
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| 86 | <samp>uchar.h</samp>. These character constants are valid even if
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| 87 | <samp>uchar.h</samp> is not included, but some uses of them may be
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| 88 | inconvenient without including it to declare those type names.
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| 89 | </p>
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| 90 | <p>The character represented in a wide character constant can be an
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| 91 | ordinary ASCII character. <code>L'a'</code>, <code>u'a'</code> and <code>U'a'</code>
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| 92 | are all valid, and they are all equal to <code>'a'</code>.
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| 93 | </p>
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| 94 | <p>In all three kinds of wide character constants, you can write a
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| 95 | non-ASCII Unicode character in the constant itself; the constant’s
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| 96 | value is the character’s Unicode character code. Or you can specify
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| 97 | the Unicode character with an escape sequence (see <a href="Unicode-Character-Codes.html">Unicode Character Codes</a>).
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| 98 | </p>
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| 99 | <hr>
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| 100 | <div class="header">
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| 101 | <p>
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| 102 | Next: <a href="Wide-String-Constants.html" accesskey="n" rel="next">Wide String Constants</a>, Previous: <a href="Unicode-Character-Codes.html" accesskey="p" rel="prev">Unicode Character Codes</a>, Up: <a href="Constants.html" accesskey="u" rel="up">Constants</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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