錯誤在PHP頁面

Question

，我發現了以下錯誤：

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 

它發生時在session_start()，當我刷新cookie。

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相同的頁面（和代碼）在另一臺機器上工作。 唯一的區別是安裝的Apache服務器（在我的2.2.21和另一個是2.2.17）。

php版本是5.2.17，php.ini文件是一樣的。

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我該如何解決這種情況？

Answer 1

這個錯誤主要發生在您調用session_start（）之前從php腳本發送內容/輸出的地方。

通常在<?php之前，您可能會有空間或其他符號/字母。 在你的情況下，問題是在monitor.php第2行 - 您可能在調用之前恰好回顯session_start()

Answer 2

php.ini文件是否相同？對我來說，聽起來像其中一個可能有output_buffering = on，而另一個（失敗的那個）有output_buffering = off。

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

很顯然，這是默認取決於什麼樣的PHP安裝完成。

Answer 3

您應該檢查文件monitor.php的第二行，因爲此行似乎向瀏覽器輸出了一些文本。

輸出文字後不能執行session_start()。