實驗1php
var_dump(memory_get_usage()); $a = 'test'; var_dump(memory_get_usage()); $b = & $a; var_dump(memory_get_usage()); $a = ''; var_dump(memory_get_usage()); $b = ''; var_dump(memory_get_usage());
輸出函數
int(2503368) int(2503400) int(2503400) int(2503400) int(2503400)
實驗二code
var_dump(memory_get_usage()); $a = 'test'; var_dump(memory_get_usage()); $b = & $a; var_dump(memory_get_usage()); unset($a); var_dump(memory_get_usage()); unset($b); var_dump(memory_get_usage());
輸出內存
int(2503344) int(2503376) int(2503376) int(2503376) int(2503344)
結論get
賦值爲null不能釋放內存,函數unset()只有unset全部引用的變量,當內存的引用計數爲0時,內存纔回被釋放。class