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POA pointer/array issue in C
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copied!<p>I have followed the following webpage:</p> <p><a href="http://www.1024cores.net/home/lock-free-algorithms/reader-writer-problem/improved-lock-free-seqlock" rel="nofollow">http://www.1024cores.net/home/lock-free-algorithms/reader-writer-problem/improved-lock-free-seqlock</a></p> <p>the source is like following:</p> <pre><code>struct data_t { int seq; // sequence number int data [1024]; // user data }; struct seqlock_t { data_t* current; data_t pool [16]; // 16 user objects are held }; seqlock_t sl; </code></pre> <p>The structure is quite simple, what confuses me is the following:</p> <pre><code>data_t* d0 = sl.current; // load-consume int idx = (sl.current - sl.pool + 1) % 16; data_t* d = &sl.pool[idx]; </code></pre> <p>The <code>sl.current</code> is a pointer, <code>sl.pool</code> is? What current - pool can achieve? in <code>c language</code> view, how should I explain this statement? </p> <pre><code>int idx = (sl.current - sl.pool + 1) % 16; </code></pre> <p>Edit :</p> <p>Thanks for all information , it help a lot !!! in my own coding style would use int idx = (sl.current - &[sl.pool[0]) + 1) % 16; now I know &(sl.pool[0]) is the same with sl.pool !!! I should figure it out , the following example , what I read before , showes pointer/array ....</p> <pre><code>void display(int *p) { int idx ; printf("(%d)(%d)\n",*p,p[1]) ; } int main() { int i,Arr[10] ; for(i=0;i<10;i++) Arr[i] = i + 100; display(Arr) ; } </code></pre> <p>Yes , I can use display(Arr) and display(&Arr[0]) , they are the same ~!!</p>

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