caller has no way knowing whether the function will modify the argument?

Is it true that the caller has no way to know whether the function it
is calling uses

function foo($a)

or

function foo(&$a)

so the caller never knows whether it is "pass by value" or "pass by
reference" and so won't know whether the argument can be modified or
not?

Re: caller has no way knowing whether the function will modify the argument?

On Sep 26, 7:13 pm, Summercool wrote:
>
> Is it true that the caller has no way to know whether the function it
> is calling uses
>
> function foo($a)
>
> or
>
> function foo(&$a)
>
> so the caller never knows whether it is "pass by value" or "pass by
> reference" and so won't know whether the argument can be modified or
> not?

That's what documentation is for...

Cheers,
NC