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exit

(PHP 4, PHP 5)

exit — 输出一个消息并且退出当前脚本

说明

void exit ([ string $status ] )

void exit ( int $status )

中止脚本的执行。尽管调用了 exit() ， Shutdown函数以及 object destructors 总是会被执行。

参数

status

如果 status 是一个字符串，在退出之前该函数会打印 status 。

如果 status 是一个 integer ，该值会作为退出状态码，并且不会被打印输出。退出状态码应该在范围0至254，不应使用被PHP保留的退出状态码255。状态码0用于成功中止程序。

Note: PHP >= 4.2.0 当 status 是一个 integer ，不会打印输出。

返回值

没有返回值。

范例

Example #1 exit() 例子

  <?php

$filename  =  '/path/to/data-file' ;
 $file  =  fopen ( $filename ,  'r' )
    or exit( "unable to open file ( $filename )" );

 ?>

Example #2 exit() 状态码例子

  <?php

 //exit program normally
 exit;
exit();
exit( 0 );

 //exit with an error code
 exit( 1 );
exit( 0376 );  //octal

 ?>

Example #3 无论如何，Shutdown函数与析构函数都会被执行

  <?php
 class  Foo
 {
    public function  __destruct ()
    {
        echo  'Destruct: '  .  __METHOD__  .  '()'  .  PHP_EOL ;
    }
}

function  shutdown ()
{
    echo  'Shutdown: '  .  __FUNCTION__  .  '()'  .  PHP_EOL ;
}

 $foo  = new  Foo ();
 register_shutdown_function ( 'shutdown' );

exit();
echo  'This will not be output.' ;
 ?>

以上例程会输出：

Shutdown: shutdown()
 Destruct: Foo::__destruct()

注释

Note: 因为是一个语言构造器而不是一个函数，不能被可变函数调用。

Note:

该语法结构等同于 die() 。

参见

register_shutdown_function() - Register a function for execution on shutdown

用户评论:

[#1] m dot libergolis at gmail dot com [2015-08-18 06:44:12]

In addition to "void a t informance d o t info", here's a one-liner that requires no constant:

<?php basename($_SERVER['PHP_SELF']) == basename(__FILE__) && die('Thou shall not pass!'); ?>

Placing it at the beginning of a PHP file will prevent direct access to the script.

To redirect to / instead of dying:

<?php if (basename($_SERVER['PHP_SELF']) == basename(__FILE__)) { if (ob_get_contents()) ob_clean(); // ob_get_contents() even works without active output buffering header('Location: /'); die; } ?>

Doing the same in a one-liner:

<?php basename($_SERVER['PHP_SELF']) == basename(__FILE__) && (!ob_get_contents() || ob_clean()) && header('Location: /') && die; ?>

A note to security: Even though $_SERVER['PHP_SELF'] comes from the user, it's safe to assume its validity, as the "manipulation" takes place _before_ the actual file execution, meaning that the string _must_ have been valid enough to execute the file. Also, basename() is binary safe, so you can safely rely on this function.

[#2] theonenkl at gmail dot com [2015-04-21 15:33:37]

A side-note for the use of exit with finally: if you exit somewhere in a try block, the finally won't be executed. Could not sound obvious: for instance in Java you never issue an exit, at least a return in your controller; in PHP instead you could find yourself exiting from a controller method (e.g. in case you issue a redirect).

Here follows the POC:

<?php echo "testing finally wit exit\n"; try { echo "In try, exiting\n"; exit; } catch(Exception $e) { echo "catched\n"; } finally { echo "in finally\n"; } echo "In the end\n"; ?>

This will print:

testing finally wit exit
In try, exiting

[#3] alexyam at live dot com [2012-04-09 16:19:10]

When using php-fpm, fastcgi_finish_request() should be used instead of register_shutdown_function() and exit()

For example, under nginx and php-fpm 5.3+, this will make browsers wait 10 seconds to show output:

<?php echo "You have to wait 10 seconds to see this.<br>"; register_shutdown_function('shutdown'); exit; function shutdown(){ sleep(10); echo "Because exit() doesn't terminate php-fpm calls immediately.<br>"; } ?>

This doesn't:

<?php echo "You can see this from the browser immediately.<br>"; fastcgi_finish_request(); sleep(10); echo "You can't see this form the browser."; ?>

[#4] nicoladinh at gmail dot com [2010-12-02 00:09:08]

Calling to exit() will flush all buffers started by ob_start() to default output.

[#5] dexen dot devries at gmail dot com [2010-11-03 05:54:16]

If you want to avoid calling exit() in FastCGI as per the comments below, but really, positively want to exit cleanly from nested function call or include, consider doing it the Python way:

define an exception named `SystemExit', throw it instead of calling exit() and catch it in index.php with an empty handler to finish script execution cleanly.

<?php // file: index.php class SystemExit extends Exception {} try { } catch (SystemExit $e) { } // end of file: index.php // some deeply nested function or .php file if (SOME_EXIT_CONDITION) throw new SystemExit(); // instead of exit() ?>

[#6] vincent dot laag at gmail dot com [2010-09-24 12:51:31]

Don't use the exit() function in the auto prepend file with fastcgi (linux/bsd os).
It has the effect of leaving opened files with for result at least a nice "Too many open files ..." error.

[#7] matt at serverboy dot net [2010-03-23 12:11:57]

It should be noted that if building a site that runs on FastCGI, calling exit will generate an error in the server's log file. This can quickly fill up.

Also, using exit will diminish the performance benefit gained on FastCGI setups. Instead, consider using code like this:

<?php if(  )     echo "Invalid request"; else {      } ?>

I've also seen developers get around this issue with FastCGI by wrapping their code in a switch statement and using breaks:

index.php:
<?php switch(true) {     case true:         require('application.php'); } ?>

application.php:
<?php if($x > $y) {     echo "Sorry, that didn't work.";     break; } // ... ?>

It does carry some overhead, but compared to the alternative, it does the job well.

[#8] albert at removethis dot peschar dot net [2009-05-05 11:50:27]

jbezorg at gmail proposed the following:

<?php if($_SERVER['SCRIPT_FILENAME'] == __FILE__ )   header('Location: /'); ?>

After sending the `Location:' header PHP _will_ continue parsing, and all code below the header() call will still be executed.  So instead use:

<?php if($_SERVER['SCRIPT_FILENAME'] == __FILE__) {   header('Location: /');   exit; } ?>

[#9] jbezNULLorg at gmNULLail dot com [2009-02-24 12:26:57]

If you are retroactively going through included files to prevent them from being accessed, you can use the following.

<?php if($_SERVER['SCRIPT_FILENAME'] == __FILE__ ) header('location: /'); // or exit(); // rest of code ?>

[#10] void a t informance d o t info [2008-10-26 14:11:00]

To rich dot lovely at klikzltd dot co dot uk:

Using a "@" before header() to suppress its error, and relying on the "headers already sent" error seems to me a very bad idea while building any serious website.

This is *not* a clean way to prevent a file from being called directly. At least this is not a secure method, as you rely on the presence of an exception sent by the parser at runtime.

I recommend using a more common way as defining a constant or assigning a variable with any value, and checking for its presence in the included script, like:

in index.php:
<?php define ('INDEX', true); ?>

in your included file:
<?php if (!defined('INDEX')) { die('You cannot call this script directly !'); } ?>

BR.

Ninj

[#11] emils at tvnet dot lv [2003-08-23 08:14:28]

Note, that using exit() will explicitly cause Roxen webserver to die, if PHP is used as Roxen SAPI module. There is no known workaround for that, except not to use exit(). CGI versions of PHP are not affected.

[#12] mbostrom at paragee dot com [2003-02-26 12:45:49]

In PHP 4.3.1 (and possibly 4.3.0), running scripts from the command line works a lot better.  This is probably because 4.3.x has a whole new CLI mode.

Specifically, exit status is now returned (to the shell) as you would expect.  This is a godsend for writing embedded email processing scripts, as much email infrastructure (fetchmail, qmail, mutt, etc.) is dependant upon correctly returned status codes, and the inability to return a status code (as in PHP 4.2.x) is an insurmountable obstacle.

$_SERVER["argv"] is also always available in 4.3.x, I think, whereas in 4.2.x php.ini could prevent it from being available.

(On the downside, I had to ./configure --without-mysql in order to get 4.3.1 to compile on RedHat 8.0.  Otherwise there was what looked like a fatal compile warning (that I might also have been able to ignore somehow).

The "fatal warning" FYI:
ext/mysql/libmysql/my_tempnam.o: In function `my_tempnam':
ext/mysql/libmysql/my_tempnam.c:103: the use of `tempnam' is dangerous, better use `mkstemp'

Changing the code from tempnam to mkstemp would probably not be overly complicated, but it is non-trivial.)

[#13] shaun at NOshatSPAM dot net [2002-08-09 04:13:39]

return may be preferable to exit in certain situations, especially when dealing with the PHP binary and the shell.

I have a script which is the recipient of a mail alias, i.e. mail sent to that alias is piped to the script instead of being delivered to a mailbox. Using exit in this script resulted in the sender of the email getting a delivery failure notice. This was not the desired behavior, I wanted to silently discard messages which did not satisfy the script's requirements.

After several hours of trying to figure out what integer value I should pass to exit() to satisfy sendmail, I tried using return instead of exit. Worked like a charm. Sendmail didn't like exit but it was perfectly happy with return. So, if you're running into trouble with exit and other system binaries, try using return instead.

[#14] devinemke at devinemke dot com [2002-01-11 00:38:15]

If you are using templates with numerous includes then exit() will end you script and your template will not complete (no </table>, </body>, </html> etc...). Rather than having complex nested conditional logic within your content, just create a "footer.php" file that closes all of your HTML and if you want to exit out of a script just include() the footer before you exit().

for example:

include ('header.php');
blah blah blah
if (!$mysql_connect) {
echo "unable to connect";
include ('footer.php');
exit;
}
blah blah blah
include ('footer.php');