Section 2.4. System Configuration

2.4. System Configuration

Now that you have PHP and your web server up and running, you will probably want to configure PHP to your liking. All of PHP's settings are available in its php.ini file, which, if you followed these installation instructions, is available either in /usr/local/lib/php (Unix) or c:\windows\php.ini (Windows). Open this in your text editor of choice (you will need to be root on Unix).

A list of popular options, what they do, and their default values (if you use php.ini-recommended as the default) is given in Table 2-2. Note that lines starting with a semicolon (;) are comments, and are ignored by PHP.

Table 2-2. Configuration options for PHP

Option	Meaning	Default
assert.active	Enables the assert( ) function	On
display_errors	Sets whether PHP should output error messages to the screen	Off
error_reporting	Decides what types of errors PHP should notify you of	E_ALL
expose_php	Allows PHP to identify itself to clients through the web server	On
extension	Loads a PHP extension	N/A
extension_dir	Sets the directory where PHP should look for extensions	./
file_uploads	Decides whether PHP should accept users uploading files	On
log_errors	Determines whether PHP should store error messages in a log file	On
magic_quotes_gpc	Determines whether PHP should automatically run form data through addslashes( ) before you get it	Off
max_execution_time	Determines how long a script may run for before timing out	30 seconds
mbstring.func_overload	Converts non-multibyte string functions to their multibyte equivalents	0
memory_limit	Sets the maximum amount of RAM a PHP script may consume	8M
precision	Determines number of decimal places for floating-point numbers	14
register_globals	Decides whether all superglobal arrays should have their elements exported to the global scope	Off
safe_mode	Enables high security mode for shared server environments	Off
session.save_path	Selects the directory in which session data will be stored	/tmp
short_open_tags	Enables <? for opening PHP code blocks	On
SMTP	Sets the mail server address for the mail( ) function.
variables_order	Determines the order in which variables are parsed: G is GET, P is POST, C is cookie, and S is session	GPCS

If you intend to use sessions, make sure you set the sessiondir variable to a directory that a) exists, and b) Apache has read and write access to.