PHP 选项/信息 函数
在线手册：中文 英文
PHP手册

ini_set

(PHP 4, PHP 5)

ini_set — Sets the value of a configuration option

说明

string ini_set ( string $varname , string $newvalue )

Sets the value of the given configuration option. The configuration option will keep this new value during the script's execution, and will be restored at the script's ending.

参数

varname

Not all the available options can be changed using ini_set(). There is a list of all available options in the appendix.

newvalue

The new value for the option.

返回值

Returns the old value on success, FALSE on failure.

范例

Example #1 Setting an ini option

<?php
echo ini_get('display_errors');

if (!ini_get('display_errors')) {
    ini_set('display_errors', 1);
}

echo ini_get('display_errors');
?>

参见

PHP 选项/信息 函数
在线手册：中文 英文
PHP手册
PHP手册 - N: Sets the value of a configuration option

用户评论:

Nathan (09-Nov-2011 04:56)

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 (12-Aug-2009 09:46)

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 (31-Oct-2006 01:19)

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 (31-Mar-2006 09:36)

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 (10-Jan-2006 07:30)

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 (05-Sep-2004 03:54)

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 (05-Sep-2004 02:49)

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 (14-Aug-2004 02:54)

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 (18-Mar-2003 02:42)

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 (30-Sep-2002 04:26)

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 (12-Jun-2002 06:04)

[[[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 (14-Mar-2002 02:13)

[[[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;
}
?>