107 lines
4.3 KiB
HTML
107 lines
4.3 KiB
HTML
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<head>
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<title>Using the GNU Compiler Collection (GCC): Subscripting</title>
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<link href="Option-Index.html#Option-Index" rel="index" title="Option Index">
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<link href="index.html#SEC_Contents" rel="contents" title="Table of Contents">
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<link href="C-Extensions.html#C-Extensions" rel="up" title="C Extensions">
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<link href="Pointer-Arith.html#Pointer-Arith" rel="next" title="Pointer Arith">
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<a name="Subscripting"></a>
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<div class="header">
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<p>
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Next: <a href="Pointer-Arith.html#Pointer-Arith" accesskey="n" rel="next">Pointer Arith</a>, Previous: <a href="Escaped-Newlines.html#Escaped-Newlines" accesskey="p" rel="prev">Escaped Newlines</a>, Up: <a href="C-Extensions.html#C-Extensions" accesskey="u" rel="up">C Extensions</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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</div>
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<hr>
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<a name="Non_002dLvalue-Arrays-May-Have-Subscripts"></a>
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<h3 class="section">6.22 Non-Lvalue Arrays May Have Subscripts</h3>
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<a name="index-subscripting"></a>
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<a name="index-arrays_002c-non_002dlvalue"></a>
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<a name="index-subscripting-and-function-values"></a>
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<p>In ISO C99, arrays that are not lvalues still decay to pointers, and
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may be subscripted, although they may not be modified or used after
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the next sequence point and the unary ‘<samp>&</samp>’ operator may not be
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applied to them. As an extension, GNU C allows such arrays to be
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subscripted in C90 mode, though otherwise they do not decay to
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pointers outside C99 mode. For example,
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this is valid in GNU C though not valid in C90:
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</p>
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<div class="smallexample">
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<pre class="smallexample">struct foo {int a[4];};
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struct foo f();
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bar (int index)
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{
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return f().a[index];
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}
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</pre></div>
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