阻塞(等待)模式：
1 <?php 2 $fp = fopen("lock.txt", "r"); 3 if(flock($fp,LOCK_EX)) 4 { 5 //.. do something 6 flock($fp,LOCK_UN);//解锁 7 } else { 8 ???echo ‘lock!‘; 9 }10 fclose($fp);11 ?>非阻塞模式：
<?php$fp = fopen("lock.txt", "r");if(flock($fp,LOCK_EX | LOCK_NB)){ //..do something flock($fp,LOCK_UN);//解锁} else { echo "系统繁忙，请稍后再试";}fclose($fp);?>php 文件锁解决并发问题
原文地址：https://www.cnblogs.com/dawuge/p/9407960.html