eval
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
exit
(PHP 4, PHP 5)
exit — Output a message and terminate the current script
说明
void exit
([ string $status
] )
void exit
( int $status
)
Terminates execution of the script.
参数
- status
-
If status is a string, this function prints the status just before exiting.
If status is an integer, that value will also be used as the exit status. Exit statuses should be in the range 0 to 254, the exit status 255 is reserved by PHP and shall not be used. The status 0 is used to terminate the program successfully.
Note: PHP >= 4.2.0 does NOT print the status if it is an integer.
返回值
无返回值。
范例
Example#1 exit() example
<?php
$filename = '/path/to/data-file';
$file = fopen($filename, 'r')
or exit("unable to open file ($filename)");
?>
Example#2 exit() status example
<?php
//exit program normally
exit;
exit();
exit(0);
//exit with an error code
exit(1);
exit(0376); //octal
?>
add a note
User Contributed Notesexit
void a t informance d o t info
26-Oct-2008 03:11
26-Oct-2008 03:11
rich dot lovely at klikzltd dot co dot uk
19-Jul-2008 06:24
19-Jul-2008 06:24
usefull feature:
@header("location: path/to/home/page") and exit();
EG:
We have a "modular" website, with common header and footer files, and different content modules, eg photos, usually accessed via index.php?p=photos
index.php:
<?php include "head.php";
include $_GET['p'] . ".php"; //Change this - SECURITY!
include "foot.php";
?>
photos.php:
<?php
@header("location: index.php?p=photos") and exit();
//Code to display photos etc
?>
If someone tries to access photos.php, which doesn't produce a full html page by definition, the header directive sends them to the full version, returns true, and therefore runs the exit() function.
If they go in normally, the header function should die with the "headers already sent" error, which is supressed by the @ and returns false, preventing the exit statement from running due to lazy execution.
dan
11-Jul-2007 03:11
11-Jul-2007 03:11
In relation to the below comment, you may find that using the following may be more appropriate:
<?php
# ... user has pressed log out, cookies have been wiped, etc.
// Stay on the same page at time of logout (useful if a page is also available to anyone who isn't logged in
header ("Location: http://" . $_SERVER['HTTP_HOST'] . $_SERVER['PHP_SELF']);
?>
Of course $_SERVER['PHP_SELF'] can be omitted if you wish to redirect to the root directory of the site (http://www.example.com) or a path of your choosing can be used instead.
Alternatively, if you've a solid system implemented and logged out users can access the page too, you can continue with showing the page without using exit() or header().
Roumen Semov
16-Feb-2006 11:54
16-Feb-2006 11:54
Please note in PHP "exit(0)" or simply "exit" returns true.
Any other value but zero will return false. This is good to know in case you are writing command-line php scripts where you need the result of the php script to determine if the next script will run. Example:
shell> ./my_php_script && echo "It ran successfully!"
If you know my_php_script can break somewhere you could do a conditional with an "exit(-1)" and then if the script breaks the command after the && will not execute.
nospam at mydomain dot com
27-Sep-2004 02:12
27-Sep-2004 02:12
Using return instead of exit is to prefer when you want the script that you have included inside another script to die but continue to execute the main script.
// Radcliff
emils at tvnet dot lv
23-Aug-2003 08:14
23-Aug-2003 08:14
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.
mbostrom at paragee dot com
26-Feb-2003 12:45
26-Feb-2003 12:45
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.)
shaun at NOshatSPAM dot net
09-Aug-2002 04:13
09-Aug-2002 04:13
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.
iamfast at tampabay dot rr dot com
13-Jul-2002 08:12
13-Jul-2002 08:12
If you are working with images or something of the sort that is not html, and use auto appending, call exit before you close your php tag, so that the footer is not included, corrupting the end of the file.
--Nate
devinemke at devinemke dot com
11-Jan-2002 12:38
11-Jan-2002 12:38
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');