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| <title>Using the GNU Compiler Collection (GCC): Subscripting</title> |
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| <a name="Non_002dLvalue-Arrays-May-Have-Subscripts"></a> |
| <h3 class="section">6.22 Non-Lvalue Arrays May Have Subscripts</h3> |
| <a name="index-subscripting"></a> |
| <a name="index-arrays_002c-non_002dlvalue"></a> |
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| <a name="index-subscripting-and-function-values"></a> |
| <p>In ISO C99, arrays that are not lvalues still decay to pointers, and |
| may be subscripted, although they may not be modified or used after |
| the next sequence point and the unary ‘<samp>&</samp>’ operator may not be |
| applied to them. As an extension, GNU C allows such arrays to be |
| subscripted in C90 mode, though otherwise they do not decay to |
| pointers outside C99 mode. For example, |
| this is valid in GNU C though not valid in C90: |
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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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| return f().a[index]; |
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