从函数内部修改参数指向的对象是否符合标准？

Question

如果一个函数修改了它接收到的指向的对象，那么在函数调用之后，调用方是否可以看到该更改？

单位一：

void foo(int *bar) { *bar = 42; }

单位b：

extern void foo(int *bar);

void baz(void) {
   int qux = 0;
   foo(&qux);
   // Is qux guaranteed to be 42 now?
}

我很确定是的，但我想根据 C 标准对其进行备份。

Answer 1

"I'm quite sure it is but I would like to have it backed up based on the C standard."

虽然这是一个非常基本的问题（您可能已经知道），但这里是提供您想要的完整标准合规性的引述：

ISO/IEC 9899:2018 (C18)，“函数调用”6.5.2.2/4（强调我的）：

"An argument may be an expression of any complete object type. In preparing for the call to a function, the arguments are evaluated, and each parameter is assigned the value of the corresponding argument.97)

97) A function can change the values of its parameters, but these changes cannot affect the values of the arguments. On the other hand, it is possible to pass a pointer to an object, and the function can then change the value of the object pointed to. A parameter declared to have array or function type is adjusted to have a pointer type as described in 6.9.1."

从函数内部修改参数指向的对象是否符合标准？

Is modifying an object pointed to by a parameter from inside of a function standard-compliant?

c

parameters

pointers

function

language-lawyer