PHP – Static Variables

Scope can be defined as the range of availability a variable has to the program in which it is declared. PHP variables can be one of four scope types −

• Local Variables
• Global Variables
• Static Variables
• Function Parameters

Static Variables

The final type of variable scoping that I discuss is known as static. In contrast to the variables declared as function parameters, which are destroyed on the function's exit, a static variable will not lose its value when the function exits and will still hold that value should the function be called again.

You can declare a variable to be static simply by placing the keyword STATIC in front of the variable name.

<?php
   function keep_track() {
      STATIC $count = 0;
      $count++;
      print $count;
      print "\n";
   }
   
   keep_track();
   keep_track();
   keep_track();
?>

This will produce the following result −

1
2
3