php页面中的错误[重复]

Question

我收到以下错误：

Warning: session_start() [function.session-start]: Cannot send session cookie - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 3
Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 3
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 20
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 24
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 25
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 38
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 39
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 52
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 52
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 38
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 39
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 52
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 52
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 76
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 77
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 96
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 96
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 96
Warning: Cannot modify header information - headers already sent by (output started at C:\Apache2.2\htdocs\monitor.php:2) in C:\Apache2.2\htdocs\monitor.php on line 96

每当在session_start() 中以及当我刷新cookie 时都会发生这种情况。

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同一页面（和代码）正在另一台机器上运行。 唯一的区别是安装的 Apache 服务器（我的是 2.2.21，另一个是 2.2.17）。

php版本为5.2.17，php.ini文件相同。

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我该如何解决这种情况？

Answer 1

大多数情况下，在调用 session_start() 之前从 php 脚本发送内容/输出时会发生此错误。

通常在<?php 之前，您可能有空格或其他符号/字母。 在您的情况下，问题出在 monitor.php 第 2 行 - 您可能会在调用 session_start()

之前回显

Answer 2

php.ini 文件是否相同？ 对我来说，其中一个文件可能有 output_buffering=on，而另一个（失败的文件）有 output_buffering=off。 p>

http://www.php.net/manual/en/outcontrol.configuration.php

显然，哪个是默认值取决于安装了哪种 PHP。

Answer 3

您应该检查文件monitor.php 的第二行，因为该行似乎向浏览器输出了一些文本。

你不能在输出文本后执行session_start()。