php 传引用的用例

 

print_r(a2());
function a2()
{
    $arr['a'] = 300;
    foreach($arr as $k => &$v)
    {
        a1($v);
    }
    return $arr;
}
function a1(&$v)
{
    $v = 100;
}
exit;

输出：

Array ( [a] => 100 )