PHP是一种服务器端语言. time()函数将解析为该服务器的系统时间.如果服务器正在运行NTP守护程序，则它将知道leap秒并进行相应调整. PHP不知道这一点，但是系统知道.

PHP is a serverside language. The time() function will resolve to the system time of that server. If the server is running an NTP daemon then it will be leap second aware and adjust accordingly. PHP has no knowledge of this, but the system does.