Fatal error: Uncaught Error: Call to undefined function function_tool() in D:\wwwroot\jiahong.com\ThinkPHP\ThinkPHP.php:15 Stack trace: #0 D:\wwwroot\jiahong.com\index.php(6): require() #1 {main} thrown in D:\wwwroot\jiahong.com\ThinkPHP\ThinkPHP.php on line 15