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phpstaticextending-classes

do extended classes inherit static var values (PHP)?


If I have a base class that contains a static var, I then set this static var, and then have a class that extends the base class, will the extended class retain the value of the static var that I have already set in the base class?


Solution

  • Yes, although they're different variables, the static variables in both classes are in the same reference set.

    You can break this reference set though, by using reference assignment (=&) or by redeclaring it in the extended class:

    class base {
        public static $var;
    }
    class extended extends base {}
    
    extended::$var = 8; // base::$var == 8
    $t = 6;
    extended::$var =& $t; // base::$var == 8; extended::$var == 6
    
    class base {
        public static $var;
    }
    class extended extends base {
        public static $var;
    }
    
    extended::$var = 8; // base::$var == null; extended::$var == 8