What does ampersand & do in a function name? : <p>I understand that having an ampersand before declaring a variable in a function is a call by reference, and it will modify variable i created in my <code>main</code> function.</p>

<pre><code>int my_func(int &amp;my_var){
    my_var += 9;
    return my_var;
}


int main(void){
    int some_var = 1;
    my_func(some_var); // value of some_var is now 10
    return 0;
</code></pre>

<p>However, what does an ampersand before a function name do? For example</p>

<pre><code>int &amp;my_func(int &amp;my_var){
    my_var +=9;
    return my_var;
}
</code></pre>
