函数指针与函数引用

In the code below, function-pointer and what i considered as "function-reference" seems to have identical semantics:

#include <iostream>
using std::cout;

void func(int a) {
    cout << "Hello" << a << '
';
}
void func2(int a) {
    cout << "Hi" << a << '
';
}

int main() {
    void (& f_ref)(int) = func;
    void (* f_ptr)(int) = func;

    // what i expected to be, and is, correct:
    f_ref(1);
    (*f_ptr)(2);

    // what i expected to be, and is not, wrong:
    (*f_ref)(4); // i even added more stars here like (****f_ref)(4)
    f_ptr(3);    // everything just works!

    // all 4 statements above works just fine

    // the only difference i found, as one would expect:
//  f_ref = func2; // ERROR: read-only reference
    f_ptr = func2; // works fine!
    f_ptr(5);

    return 0;
}

我在 Fedora/Linux 中使用了 gcc 4.7.2 版