php配置文件详解

[PHP]
;;;;;;;;;;;;;;;;;;;
; About php.ini   ;
;;;;;;;;;;;;;;;;;;;
; PHP's initialization file, generally called php.ini, is responsible for
; configuring many of the aspects of PHP's behavior.
; PHP attempts to find and load this configuration from a number of locations.
; The following is a summary of its search order:
; 1. SAPI module specific location.
; 2. The PHPRC environment variable. (As of PHP 5.2.0)
; 3. A number of predefined registry keys on Windows (As of PHP 5.2.0)
; 4. Current working directory (except CLI)
; 5. The web server's directory (for SAPI modules), or directory of PHP
; (otherwise in Windows)
; 6. The directory from the --with-config-file-path compile time option, or the
; Windows directory (C:\windows or C:\winnt)
; See the PHP docs for more specific information.
; http://php.net/configuration.file
; The syntax of the file is extremely simple.  Whitespace and Lines
; beginning with a semicolon are silently ignored (as you probably guessed).
; Section headers (e.g. [Foo]) are also silently ignored, even though
; they might mean something in the future.
; Directives following the section heading [PATH=/www/mysite] only
; apply to PHP files in the /www/mysite directory.  Directives
; following the section heading [HOST=www.example.com] only apply to
; PHP files served from www.example.com.  Directives set in these
; special sections cannot be overridden by user-defined INI files or
; at runtime. Currently, [PATH=] and [HOST=] sections only work under
; CGI/FastCGI.
; http://php.net/ini.sections
; Directives are specified using the following syntax:
; directive = value
; Directive names are *case sensitive* - foo=bar is different from FOO=bar.
; Directives are variables used to configure PHP or PHP extensions.
; There is no name validation.  If PHP can't find an expected
; directive because it is not set or is mistyped, a default value will be used.
; The value can be a string, a