phpscopeclosuresanonymous-function

PHP - Difference between 'use()' or 'global' to access a global variable in a closure?

Is there any kind of performance or other difference between following two cases of accessing a global variable in a closure:

Case 1:

$closure = function() use ($global_variable) {
  // Use $global_variable to do something.
}

Case 2:

$closure = function() {
  global $global_variable; 
  // Use $global_variable to do something.
}
Solution

  • There is an important difference between your two examples: 

    $global_variable = 1;

$closure = function() use ($global_variable) {
    return $global_variable; 
};

$closure2 = function() {
    global $global_variable;
    return $global_variable;
};

$global_variable = 99;

echo $closure();    // this will show 1
echo $closure2();   // this will show 99

    use takes the value of $global_variable during the definition of the closure while global takes the current value of $global_variable during execution.

    global inherits variables from the global scope while use inherits them from the parent scope.