php static变量的refcount为何是2,is_ref为何是1?
<code><?php $a = 1; xdebug_debug_zval("a"); static $b = 1; xdebug_debug_zval("b"); ?> </code>
为何执行后输出是
a: (refcount=1, is_ref=0)=1
b: (refcount=2, is_ref=1)=1
static变量和普通变量为何会有这样的区别?
回复内容:
<code><?php $a = 1; xdebug_debug_zval("a"); static $b = 1; xdebug_debug_zval("b"); ?> </code>
为何执行后输出是
a: (refcount=1, is_ref=0)=1
b: (refcount=2, is_ref=1)=1
static变量和普通变量为何会有这样的区别?
refcount是计数次数,如果为0 就是被销毁
如果用Unset 这个数会减1
is_ref是表示引用
猜想:这表变量里的内容是另一个内存地址(也就是真实的内容),然后unset只会删除这个变量,并不会删除这个内存地址里面的东西
http://php.net/manual/zh/features.gc.refcounting-basics.php

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