Are Unamed Variables in Function Call Static

Question

So we call some function in PHP:

do_something('foodabaa');
function do_something($subject)
{
  static $pattern = '~foo~';
  return preg_replace($pattern, 'bar', $subject);
}

Is the replacement value bar static, or is it dynamic so each call to the function reinitializes it?

By all means add info about other programming languages besides PHP.

Answer 1

From PHP documentation (Example #5):

function test()
{
    static $a = 0;
    echo $a."\n\r";
    $a++;
}

Now, $a is initialized only in first call of function and every time the test() function is called it will print the value of $a and increment it.

So if you will call it twice:

test();
test();

Return will be:

0
1

Lets back to your example. There is same situation, $pattern will be initialized just once.

Inside C/C++

void foo()
{
    static int a = 0;
    printf("%d", a);
    x++;
}

int main()
{
    foo();
    foo();
    return 0;
}

Output will be:

0
1

That's the common behavior in many languages which are using static variables.