从C中的另一个文件链接静态函数

Question

I have two source files: Ac and Bc

Ac has a function, call_me:

static int call_me();

void call_me_register()
{
    register_call_me(call_me);
}

As you can see, call_me function is used as variable so it has a symbol of call_me in Ao

Now, I want to call this call_me function in Bc file.

static int call_me();

void call_call_me()
{
    call_me();
}

If I try to link Bo, I've got an link error, that no such reference of call_me.

Here, the constraint is the following: I can not modify Ac for some reason. Is there a any to call 'call_me' in Ac in Bc?

Answer 1

The register function in A.cpp will presumably store a pointer to the function somewhere (hence that is the registration) and you can use that pointer to call the function. -- so looks for a function to fetch the registered call_me function.

You cannot reference the function directly -- as it is static -- and being declared static as in you sample code means that the function is hidden for the outside world.

Answer 2

静态函数在C语言中的可见性仅限于声明它们的文件。因此，如果您在Ac中声明一个静态函数并从另一个文件中调用该函数，则您会得到一个链接错误，指出该函数未被引用。希望此方法可以解决你的问题..