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POSpiral rule and 'declaration follows usage' for parsing C and C++ declarations
 

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    <p>This question follows <a href="https://stackoverflow.com/questions/3706704/whats-the-meaning-of-this-piece-of-code-void-signalint-sig-void-funcint">this other question about C declarations</a>. Reading the answer to this question, I read about the <a href="http://c-faq.com/decl/spiral.anderson.html" rel="nofollow noreferrer">spiral rule</a> and I also understood what "declaration follows usage" means.</p> <p>Ok so far. But then I read <a href="http://c-faq.com/decl/cdecl1.html" rel="nofollow noreferrer">this declaration</a>:</p> <pre><code>char *(*(*a[N])())(); </code></pre> <p>and I was wondering how to parse it with the "declaration follows usage" 'rule'. Especially for the array part.</p> <p>What I read is:</p> <pre><code>(*(*a[N])()) </code></pre> <p>is a function <code>()</code> returning a <code>char *</code>, then, dereferencing the following</p> <pre><code>(*a[N])() // 1 </code></pre> <p>is this 'function returning a <code>char*</code>', and so 1 is a 'pointer to a function returning <code>char *</code>' then I would say 'when <code>(*a[N])</code> is called, it is [previous declaration]'. At this point we have <code>(*a[N])</code> is a function returning a pointer to a function returning <code>char *</code>.</p> <p>But then I don't know how to apply this rule to distinguish between the 'pointer to array' and 'array of pointer'. </p> <p>Can someone clarify this?</p> <p>Other question: what are the rules of "precedence" in such declarations, between <code>&amp;</code> (in C++), <code>*</code>, and <code>[]</code>? [maybe "precedence" is not the correct term]</p> <hr> <p>To check if I understood the 'spiral rule' correctly, I also parse this expression below; please tell me if I am wrong.</p> <pre><code> +-----------+ | +------+ | | | +-+ | | | | ^ | | | char* (*(* a[N])())(); ^ ^ ^ ^ ^ ^ | | | | | | | | +---+ | | | +--------+ | +--------------+ </code></pre> <p>For me it is easier (loop by loop): </p> <ul> <li><code>a</code> is an array of N ...</li> <li>pointer to function returning ...</li> <li>pointer to function returning ...</li> <li><code>char *</code></li> </ul> <p>But I am maybe missing something which in that case let me obtain the correct answer but that could be wrong in another more complicated case.</p>
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