php session_start() 出错

错误提示： Warning: session_start() [function.session-start]: Cannot send session cache limiter - headers already sent

原因：      在session_start()之前如果有输出内容，会出错，

解决办法： 在session_start()之前加上ob_start();

index.php



<?php
error_reporting(-1);
ob_start();//不加会出错，无法写入session
register_shutdown_function('close');


echo 1;
 session_start();
 
$_SESSION['password']='mima2ddddddddddddddda2';

function close()
	{
		if(session_id()!=='')
			@session_write_close();
	}
?>
<a href="index2.php" >index2</a>


index2.Php

<?php
error_reporting(-1);
ob_start();//不加会出错，无法读取session

echo 1;
 session_start();

echo $_SESSION['password'];
var_dump($_SESSION);
?>
<a href="index.php" >index</a>