ini_set

Anonymous (2012-05-04 22:33:53)

Open_basedir is a tricky one.  Subsequent calls of ini_set('open_basedir', ...) will only succeed if you either leave the value unchanged, take out a directory from the list completely, or narrow a directory.  Also, you cannot add a directory to the list not already within the tightened open_basedir value.

<?php
ini_set('open_basedir', '/var/www/my_app/:/var/www/framework/');  // success if not yet set
ini_set('open_basedir', '/var/www/my_app/:/var/www/framework/');  // success still
ini_set('open_basedir', '/var/www/my_app/somepath/:/var/www/framework/'); // success
ini_set('open_basedir', '/var/www/my_app/somepath/');  // success
ini_set('open_basedir', '/var/www/my_app/'); // fails completely
ini_set('open_basedir', '/var/www/my_app/somepath/:/var/www/framework/'); // fails completely

?>

Nathan (2011-11-08 20:56:50)

Careful - in some cases, when setting zlib.output_compression to "On" via ini_set, PHP won't send the Content-type header and browsers will garble the output. Set it to the desired buffer size instead, which sends the correct header:

<?php
ini_set("zlib.output_compression", 4096);
?>

MadJoker (2009-08-12 13:46:23)

If you use gz_handler you might want to switch over to 
zlib.output_compression

This can be controlled via the ini_set control.

<?php ini_set('zlib.output_compression', 'Off'); ?>

or

<?php ini_set('zlib.output_compression', 'On'); ?>

daevid at daevid dot com (2006-10-30 17:19:25)

Be careful with setting an output_handler, as you can't use ini_set() to change it. *sigh*

In my php.ini I have this for my web pages (and I want it): 

  output_handler = ob_gzhandler

But this causes my command line scripts to not show output until the very end.

#!/usr/bin/php -q
<?php
ini_set('output_handler', 'mb_output_handler');
echo "\noutput_handler => " . ini_get('output_handler') . "\n";
?>

root@# ./myscript.php
output_handler => ob_gzhandler

Apparently (acording to Richard Lynch):

> TOO LATE!
> The ob_start() has already kicked in by this point.
> ob_flush() until there are no more buffers.

RebootConcepts.com (2006-03-31 13:36:55)

set PHP_INI_PERDIR settings in a .htaccess file with 'php_flag' like this:
php_flag register_globals off
php_flag magic_quotes_gpc on

Ron Ludwig (2006-01-10 11:30:55)

When your ISP does not allow you to add the default include directories - it might be useful to extend the 'include_path' variable:

<?php ini_set('include_path',ini_get('include_path').':../includes:');  ?>

brainiac5 dot php at aimail dot de (2004-09-05 07:54:17)

To find the apache php settings try something like this.
> cd /etc/apache2
> grep -r -n -i safe_mode_exec_dir *.conf
or
> grep -r -n -i safe_mode.*On *.conf
If you find a gererated file, obviously you need to find the source template for it, to change what's needed there.
I just wasted a sunny Sunday on searching for where the heck safe_mode_exec_dir was changed.
And yes, Local Value in phpinfo does mean 'changed between the php.ini file and here', as you would think.
If you have an automated virtual host configuration, such as confixx, php ini values can be spread across very many files.
They can be changed in apache config files, that can have any name, but usually will end on .conf, besides in .htaccess files.

klw at gmx dot at (2004-09-05 06:49:37)

To change settings from .htaccess files, it is also required that the directory permissions configured in Apache allow this.
The <Directory /foo/bar> entry in httpd.conf MUST contain "AllowOverride All" or at least "AllowOverride Options" to read PHP settings from the .htaccess file.
E.g. in Fedora Core 2, the default settings for /var/www/html/ are "AllowOverride None", so changing PHP settings via .htaccess for applications installed below /var/www/html/ will not work.

sean at php dot net (2004-08-13 18:54:28)

While this doesn't belong in the manual, it should be useful for people looking on this page for zend_optimizer.* ini options, which are commonly installed:
Information on the "zend_optimizer.optimization_level" and "zend_optimizer.enable_loader" options is available at:
http://www.zend.com/support/user_docs/ZendOptimizer/PDF/ZendOptimizer_UserGuide.pdf

davey at its-explosive dot net (2003-03-17 18:42:12)

If you set something using php_admin_value in httpd.conf it is then not possible to be set the value at runtime, even if it's NOT PHP_INI_SYSTEM.
Just an interesting note for Server admins this might come in handy to disable setting of certain things... like allow_url_fopen.
- Davey

miroslav AT simunic DOT de (2002-09-29 20:26:51)

If it's not your server and therefore you want to hide the data in your session variables from other users, it?s very useful to set the session.save_handler in your scripts to shared memory with:

<?php ini_set('session.save_handler','mm'); ?>

Remember: You have to set it in every script that uses the session variables BEFORE "session_start()" or php won't find them.

Tr909 at com dot nospam dot bigfoot (2002-06-12 10:04:45)

[[[Editors note: Yes, this is very true. Same with
register_globals, magic_quotes_gpc and others.
]]]
Many settings, although they do get set, have no influence in your script.... like upload_max_filesize will get set but uploaded files are already passed to your PHP script before the settings are changed.
Also other settings, set by ini_set(), may be to late because of this (post_max_size etc.).
beware, try settings thru php.ini or .htaccess.

johnzoet at netscape dot com (2002-03-13 18:13:49)

[[[Editors note: Just because you're able to set something 
doesn't mean it will work as expected.  Depends on the 
setting.  For example. setting register_globals at 
runtime will be of little use as its job has already 
been completed by the time it reaches your script.
]]]

When a setting can not be changed in a user script, the return value of ini_set is "empty", not "false" as you may expect.
If you check in your script for return value is "false" the script will continue processing, although the setting has not been set.
The boolean return value is used for settings that can be changed in a script. Otherwise the empty value is returned.
To test for both error conditions use:

<?php
if (empty($blnResult) or (!$blnResult)) {
   echo "setting cannot be set";
   exit;
}
?>