session_start函数

本文详细介绍了PHP中session_start()函数的用法,包括如何初始化会话、使用命名会话、处理输出缓存和输出压缩,以及如何在页面间传递会话数据。通过实例演示了如何在两个页面之间共享数据。

摘要生成于 C知道 ,由 DeepSeek-R1 满血版支持, 前往体验 >

session_start

(PHP 4, PHP 5)

session_start — Initialize session data

 Description

bool  session_start (  void )

session_start() creates a session or resumes the current one based on a session identifier passed via a GET or POST request, or passed via a cookie.

To use a named session, call session_name() before calling session_start().

When session.use_trans_sid is enabled, the session_start() function will register an internal output handler for URL rewriting.

If a user uses ob_gzhandler or similar with ob_start(), the function order is important for proper output. For example, ob_gzhandlermust be registered before starting the session.

 Return Values

This function returns TRUE if a session was successfully started, otherwise FALSE.

 Changelog

Version Description
5.3.0 If a session fails to start, then FALSE is returned. Previously TRUE was returned.
4.3.3 As of PHP 4.3.3, calling session_start() after the session was previously started will result in an error of level E_NOTICE. Also, the second session start will simply be ignored.

 Examples

Example #1 A session example: page1.php

<?php
// page1.php

session_start();

echo 
'Welcome to page #1';

$_SESSION['favcolor'] = 'green';
$_SESSION['animal']   = 'cat';
$_SESSION['time']     = time();

// Works if session cookie was accepted
echo '<br /><a href="page2.php">page 2</a>';

// Or maybe pass along the session id, if needed
echo '<br /><a href="page2.php?' SID '">page 2</a>';
?>

After viewing page1.php, the second page page2.php will magically contain the session data. Read the session reference for information on propagating session ids as it, for example, explains what the constant SID is all about.

Example #2 A session example: page2.php

<?php
// page2.php

session_start();

echo 
'Welcome to page #2<br />';

echo 
$_SESSION['favcolor']; // green
echo $_SESSION['animal'];   // cat
echo date('Y m d H:i:s'$_SESSION['time']);

// You may want to use SID here, like we did in page1.php
echo '<br /><a href="page1.php">page 1</a>';
?>

 Notes

Note:

To use cookie-based sessions, session_start() must be called before outputing anything to the browser.

Note:

Use of zlib.output_compression is recommended instead of ob_gzhandler()

Note:

This function sends out several HTTP headers depending on the configuration. See session_cache_limiter() to customize these headers.

 See Also

评论
添加红包

请填写红包祝福语或标题

红包个数最小为10个

红包金额最低5元

当前余额3.43前往充值 >
需支付:10.00
成就一亿技术人!
领取后你会自动成为博主和红包主的粉丝 规则
hope_wisdom
发出的红包
实付
使用余额支付
点击重新获取
扫码支付
钱包余额 0

抵扣说明:

1.余额是钱包充值的虚拟货币,按照1:1的比例进行支付金额的抵扣。
2.余额无法直接购买下载,可以购买VIP、付费专栏及课程。

余额充值