php - Increase static class variable in a constructor -


hi i've got following simple problem:

i'd increase static class variable each time instance of object created. i've tried this:

class task {     static $tid = 0;      function __construct()     {         $this->tid++;     }    }

this returns following error message:

notice: undefined property: task::$tid in ... on line ...

how correctly? thx in advance :)

edit:

sorry, clear approach cant work, cause static keyword indicates property not bound instance, -> doesnt work. how correctly?

$tid++ doesnt work. error: undefined variable.

as per php manual:

static properties cannot accessed through object using arrow operator ->. other php static variable, static properties may initialized using literal or constant before php 5.6; expressions not allowed.

there way. must use self keyword:

class task {     static $tid = 0;      function __construct()     {         self::$tid++;     }    }  new task(); new task();  echo task::$tid;

will output 2


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