Chapter 9. Runtime Configuration

Table of Contents
The configuration file
How to change configuration settings

The configuration file

The configuration file (called php3.ini in PHP 3, and simply php.ini as of PHP 4) is read when PHP starts up. For the server module versions of PHP, this happens only once when the web server is started. For the CGI and CLI version, it happens on every invocation.

php.ini is searched in these locations (in order):

SAPI module specific location (PHPIniDir directive in Apache 2, -c command line option in CGI and CLI, php_ini parameter in NSAPI, PHP_INI_PATH environment variable in THTTPD)
HKEY_LOCAL_MACHINE\SOFTWARE\PHP\IniFilePath (Windows Registry location)
The PHPRC environment variable
Current working directory (for CLI)
The web server's directory (for SAPI modules), or directory of PHP (otherwise in Windows)
Windows directory (C:\windows or C:\winnt) (for Windows), or --with-config-file-path compile time option

If php-SAPI.ini exists (where SAPI is used SAPI, so the filename is e.g. php-cli.ini or php-apache.ini), it's used instead of php.ini. SAPI name can be determined by php_sapi_name().

Note: The Apache web server changes the directory to root at startup causing PHP to attempt to read php.ini from the root filesystem if it exists.

The php.ini directives handled by extensions are documented respectively on the pages of the extensions themselves. The list of the core directives is available in the appendix. Probably not all PHP directives are documented in the manual though. For a complete list of directives available in your PHP version, please read your well commented php.ini file. Alternatively, you may find the the latest php.ini from CVS helpful too.

Example 9-1. php.ini example
; any text on a line after an unquoted semicolon (;) is ignored [php] ; section markers (text within square brackets) are also ignored ; Boolean values can be set to either: ; true, on, yes ; or false, off, no, none register_globals = off track_errors = yes ; you can enclose strings in double-quotes include_path = ".:/usr/local/lib/php" ; backslashes are treated the same as any other character include_path = ".;c:\php\lib"

Since PHP 5.1.0, it is possible to refer to existing .ini variables from within .ini files. Example: open_basedir = ${open_basedir} ":/new/dir".

add a note User Contributed Notes
Runtime Configuration

Trevor Blackbird > yurab.com
11-Apr-2006 01:50


You can use also use the predefined PHP_SAPI constant instead of php_sapi_name().

c dot affolter at stepping-stone dot ch
13-Mar-2006 03:38


For those people who want to use the PHPRC environment variable:

You have to specify the path to the directory containing your php.ini, not the direct path to the php.ini.



Example (php.ini resides in /your/path/php.ini):

right:

export PHPRC=/your/path



wrong:

export PHPRC=/your/path/php.ini

randy AT rcs-comp DOT com
26-May-2005 10:47


(copied from another page)

Please note that the SetEnv PHPRC "directory/to/phpini/" only works when using PHP as CGI, but _not_ when you use the PHP Apache Module!

Jorrit Schippers
26-May-2004 02:33


For IIS users: If you experience high parsetimes, try to set output_buffering to On. IIS has problems with scripts outputting many small pieces of text, and with output_buffering = On, PHP sends the whole page to IIS in one piece.

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