PHP: The configuration file - Manual (original) (raw)

The configuration file (php.ini) is read when PHP starts up. For the server module versions of PHP, this happens only once when the web server is started. For theCGI and CLI versions, it happens on every invocation.

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

• SAPI module specific location (PHPIniDir directive in Apache 2, -c command line option in CGI and CLI)
• The PHPRC environment variable.
• The location of the php.ini file can be set for different versions of PHP. The root of the registry keys depends on 32- or 64-bitness of the installed OS and PHP. For 32-bit PHP on a 32-bit OS or a 64-bit PHP on a 64-bit OS use [(HKEY_LOCAL_MACHINE\SOFTWARE\PHP] for 32-bit version of PHP on a 64-bit OS use [HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\PHP]] instead. For same bitness installation the following registry keys are examined in order:[HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x.y.z],[HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x.y] and[HKEY_LOCAL_MACHINE\SOFTWARE\PHP\x], where x, y and z mean the PHP major, minor and release versions. For 32 bit versions of PHP on a 64 bit OS the following registry keys are examined in order:[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6421Node\PHP\x.y.z],[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6421Node\PHP\x.y] and[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6421Node\PHP\x], where x, y and z mean the PHP major, minor and release versions. If there is a value for IniFilePath in any of these keys, the first one found will be used as the location of the php.ini (Windows only).
• [HKEY_LOCAL_MACHINE\SOFTWARE\PHP] or[HKEY_LOCAL_MACHINE\SOFTWARE\WOW6432Node\PHP], value ofIniFilePath (Windows only).
• Current working directory (except 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 the SAPI in use, so, for example, php-cli.ini orphp-apache.ini), it is used instead of php.ini. The SAPI name can be determined with 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.

Environment variables can be referenced within configuration values in php.ini as shown below. As of PHP 8.3.0, a fallback value can be specified that will be used when the referenced variable is not defined.

Example #1 php.ini Environment Variables

; PHP_MEMORY_LIMIT is taken from environment memory_limit = ${PHP_MEMORY_LIMIT} ; If PHP_MAX_EXECUTION_TIME is not defined, it will fall back to 30 max_execution_time = ${PHP_MAX_EXECUTION_TIME:-30}

The php.ini directives handled by extensions are documented on the respective pages of the extensions themselves. A list of the core directives is available in the appendix. Not all PHP directives are necessarily documented in this manual: for a complete list of directives available in your PHP version, please read your well commentedphp.ini file. Alternatively, you may find» the latest php.ini from Git helpful too.

Example #2 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"

It is possible to refer to existing .ini variables from within .ini files. Example: open_basedir = ${open_basedir} ":/new/dir".

Scan directories

It is possible to configure PHP to scan for .ini files in a directory after reading php.ini. This can be done at compile time by setting the--with-config-file-scan-dir option. The scan directory can then be overridden at run time by setting the PHP_INI_SCAN_DIR environment variable.

It is possible to scan multiple directories by separating them with the platform-specific path separator (; on Windows, NetWare and RISC OS; : on all other platforms; the value PHP is using is available as the [PATH_SEPARATOR](dir.constants.php#constant.path-separator) constant). If a blank directory is given in PHP_INI_SCAN_DIR, PHP will also scan the directory given at compile time via--with-config-file-scan-dir.

Within each directory, PHP will scan all files ending in.ini in alphabetical order. A list of the files that were loaded, and in what order, is available by callingphp_ini_scanned_files(), or by running PHP with the--ini option.

Assuming PHP is configured with --with-config-file-scan-dir=/etc/php.d, and that the path separator is :...

$ php PHP will load all files in /etc/php.d/*.ini as configuration files.

$ PHP_INI_SCAN_DIR=/usr/local/etc/php.d php PHP will load all files in /usr/local/etc/php.d/*.ini as configuration files.

$ PHP_INI_SCAN_DIR=:/usr/local/etc/php.d php PHP will load all files in /etc/php.d/.ini, then /usr/local/etc/php.d/.ini as configuration files.

$ PHP_INI_SCAN_DIR=/usr/local/etc/php.d: php PHP will load all files in /usr/local/etc/php.d/.ini, then /etc/php.d/.ini as configuration files.

Found A Problem?

weili ¶

4 years ago

For someone who's also wondering.

PHP can work even if there is no configuration file(php.ini) loaded,
it will simply applies the default values to directives.

grzegorz129 at gmail dot com ¶

5 months ago

It is worth noting that  $PHP_INI_SCAN_DIR is **not** recursive, which offers flexibility in organizing configuration in base-environment fashion:

$ mkdir -p /tmp/php_conf/prod /tmp/php_conf/dev 
$ touch /tmp/php_conf/php.base.ini /tmp/php_conf/prod/php.ini /tmp/php_conf/dev/php.ini
$ export PHP_INI_SCAN_DIR="/tmp/php_conf:/tmp/php_conf/dev"
$ php --ini
//...
Scan for additional .ini files in: /tmp/php_conf:/tmp/php_conf/dev
Additional .ini files parsed:      /tmp/php_conf/php.base.ini,
/tmp/php_conf/dev/php.ini

Such behavior can be used with docker where whole a subtree of configs is mounted into a dev-container, with ability to control which set of files is loaded using an environment variable.

Pictor13 ¶

2 years ago

Notice that `error_reporting` CANNOT be interpolated with an environment variable (e.g. `error_reporting = ${PHP_ERROR_REPORTING}`).

`error_reporting` is treated differently than other directives:
if assigned an environment variable, this will be silently ignored and replaced with value `0` (aka no-reporting).

I couldn't find documentation about it.
Is maybe an info that should be added in https://github.com/php/php-src/blob/8f5156fcba9906664ecd97e4c279ee980e522121/php.ini-production#L451-L500 ?

I am not aware if this specific behavior affects only `error_reporting` or also other directive.