Difference between char[N] and char (&)[N] in parameter list

Question

The following code doesn't compile:

template <int N>
void f(char[N]) {}

int main() {
  char buf[10];
  f(buf);
}

If I change the char[N] to char (&)[N], it works. So what the difference between them?

Answer 1

You have been bitten by backwards compatibility with C. When you declare a function like:

int f(char c[10]);

You declare a function whose argument is of type char *. The compiler decays the argument type for you. The problem is:

int f(char c[5]);

declares the same function. This is the way C worked, and C++ retained it for compatability.

int f(char (&c)[10]);

Declares a function whose argument is of type "reference to array (length 10) of char". C didn't have references, so there is no need to maintain backwards compatibility.

int f(char (&c)[5]);

Declares a different function - with a different argument type.