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为什么在PHP5.3中exit()之后会出现警告?_Php_Warnings_Exit - Fatal编程技术网

为什么在PHP5.3中exit()之后会出现警告?

为什么在PHP5.3中exit()之后会出现警告?,php,warnings,exit,Php,Warnings,Exit,我有一个简单的登录检查,如下所示: function send_error($message) { header ( 'Content-Type: text/html; charset=utf-8' ); header ( 'HTTP/1.0 406 Not acceptable' ); echo $message; exit (); } session_start (); if (! isset ( $_SESSION ["login"] ) || $_SESS

我有一个简单的登录检查,如下所示:

function send_error($message) {
    header ( 'Content-Type: text/html; charset=utf-8' );
    header ( 'HTTP/1.0 406 Not acceptable' );
    echo $message;
    exit ();
}
session_start ();
if (! isset ( $_SESSION ["login"] ) || $_SESSION ["login"] === "" || ! isset ( $_SESSION ["type"] )) {
    send_error ( 'ERRORE: Devi prima aver eseguito il login per poter fare logout.' );
}
问题是,如果用户尚未登录,则此部分后面的代码行会显示警告。 为什么? 不应该
exit()命令停止代码执行?这是其中一个警告:

Warning: Cannot modify header information - headers already sent by (output started at /var/www/people/ltw1313/cgi-bin/verifica_login.php:11) in /var/www/people/ltw1313/cgi-bin/verifica_post.php on line 13

尝试写入
ob_flush()
标题之前('Content Type:text/html;charset=utf-8')

我建议您阅读有关在php中发送标题的文档。和关于输出缓冲区。可能重复的