PHP closure scope problem

Question

Apparently $pid is out of scope here. Shouldn\'t it be \"closed\" in with the function? I\'m fairly sure that is how closures work in javascript for example.

Accordi

Answer 1

I think PHP is very consistent in scoping of variables. The rule is, if a variable is defined outside a function, you must specify it explicitly. For lexical scope 'use' is used, for globals 'global' is used.

For example, you can't also use a global variable directly:

$n = 5;

function f()
{
    echo $n; // Undefined variable
}

You must use the global keyword:

$n = 5;

function f()
{
    global $n;
    echo $n;
}