What exactly does “pass by reference” mean?

Question

And who has the authority to decide?

Edit: Apparently I haven\'t succeeded in formulating my question well.
I am not asking how Java\'s

Answer 1

Both of your C examples actually demonstrate pass-by-value, because C doesn't have pass-by-reference. It's just that the value that you're passing is a pointer. Pass-by-reference occurs in languages such as Perl:

sub set_to_one($)
{
    $_[0] = 1; # set argument = 1
}
my $a = 0;
set_to_one($a); # equivalent to: $a = 1

Here, the variable $a is actually passed by reference, so the subroutine can modify it. It's not modifying some object that $a is pointing to via indirection; rather, it modifies $a itself.

Java is like C in this respect, except that in Java objects are "reference types", so all you ever have (and all you can ever pass) are pointers to them. Something like this:

void setToOne(Integer i)
{
    i = 1; // set argument = 1
}

void foo()
{
    Integer a = 0;
    setToOne(a); // has no effect
}

won't actually change a; it only reassigns i.