c - 将受限指针分配给另一个指针，并使用第二个指针修改值是否合法？

Question

以下方法是否尊重“限制”契约(Contract)？

void fun(int* restrict foo) {
     int* bar = foo + 32;
     for (int i = 0; i < 32; ++i)
         *bar = 0;
}

我的猜测是否定的，但我需要澄清一下。

Answer 1

是的，它确实尊重契约(Contract)。

6.7.3 Type qualifiers

8 An object that is accessed through a restrict-qualified pointer has a special association with that pointer. This association, defined in 6.7.3.1 below, requires that all accesses to that object use, directly or indirectly, the value of that particular pointer.135) The intended use of the restrict qualifier (like the register storage class) is to promote optimization, and deleting all instances of the qualifier from all preprocessing translation units composing a conforming program does not change its meaning (i.e., observable behavior).

简而言之，在点 foo已定义(函数调用)， foo是 程序员保证成为引用它指向的对象(如果有)的唯一方法。
因此，所有其他引用这些对象的表达式都必须从该指针值派生出来(例如 bar 设置为 foo+32 )。
与往常一样，在这种情况下，背信弃义会受到未定义行为的适当惩罚。