php funciton 中的static

<?php
function t(){
    static $a= 0;
    ++ $a;
   var_dump($a);
}
$i = 3;
while ($i--){
    t();
}
结果 1 ，2，3
见手册 $a is initialized only in first call of function and every time the t() function is called it will print the value of $a and increment it.

static的变量初始化只执行一次