What is a static variable within a function?

PHP
1

PHP experts tell me a static variable within a function?

2

Doesn’t make any sense. A function is not part of a class or object, so is already ‘static’.

3

Its a type of variable that will retain its value even when program execution goes out of block scope.

Best if you read it for yourself here:

http://php.net/manual/en/language.variables.scope.php

4 

function foo() {
     static $i=0;
     echo '<p>foo has been called ',($i++),' times<p>';
}

foo();
foo();
foo();

Means of having a function or method store state. If that is the case though generally it is better to use a object or composition.

5

(Agrees it is good to read it for yourself as well, but can be a bit confusing for a beginner).

Basically a static variable is a variable which has a persistent value (it doesn’t go away when the function does), though it’s only available within that function.

For example, if I do something like:


<?php
// Example from there site.
function test()
{
    static $a = 0;
    echo $a;
    $a++;
}
?>

$a is set to zero on the first call to test() (and only the first call). Afterwards, each additional call will do the rest of that function, so $a’s value will go up every time.

It’s essentially the same as a global variable, except it can only be called from within the function it was created (if that helps at all).

6

I sit corrected…

7

=p

In just about anything else it would have made no sense. I forgot PHP had function-scope static variables until this post.