Description
int 
phpinfo ( [int what])
     Outputs a large amount of information about the current state of
     PHP. This includes information about PHP compilation options and
     extensions, the PHP version, server information and environment
     (if compiled as a module), the PHP environment, OS version
     information, paths, master and local values of configuration
     options, HTTP headers, and the PHP License.
    
     Because every system is setup differently,
     phpinfo() is commonly used to check configuration settings and for
     available predefined
     variables on a given system.  Also,
     phpinfo() is a valuable debugging tool as it
     contains all EGPCS (Environment, GET, POST, Cookie, Server) data.
    
     The output may be customized by passing one or more of the
     following constants bitwise values summed
     together in the optional what parameter.
     One can also combine the respective constants or bitwise values
     together with the or operator.
    
     
表格 1. phpinfo() options
| Name (constant) | Value | Description | 
|---|
| INFO_GENERAL | 1 | The configuration line, php.ini location, build date, Web
          Server, System and more. | 
| INFO_CREDITS | 2 | PHP 4 Credits.  See also phpcredits(). | 
| INFO_CONFIGURATION | 4 | Current Local and Master values for PHP directives.  See
          also ini_get(). | 
| INFO_MODULES | 8 | Loaded modules and their respective settings.  See also
          get_loaded_modules(). | 
| INFO_ENVIRONMENT | 16 | Environment Variable information that's also available in
          $_ENV. | 
| INFO_VARIABLES | 32 | Shows all 
          predefined variables from EGPCS (Environment, GET,
          POST, Cookie, Server). | 
| INFO_LICENSE | 64 | PHP License information.  See also the license faq. | 
| INFO_ALL | -1 | Shows all of the above.  This is the default value. | 
     
| 例子 1. phpinfo() examples | 
<?php
 // Show all information, defaults to INFO_ALL
 phpinfo();
 
 // Show just the module information.
 // phpinfo(8) yields identical results.
 phpinfo(INFO_MODULES);
 
 ?>
 | 
 | 
    注: 
      Parts of the information displayed are disabled when the
      expose_php configuration setting
      is set to off. This includes the PHP and Zend logos,
      and the credits.
     
注: 
      phpinfo() outputs plain text instead of HTML when
      using the CLI mode.
     
    See also phpversion(),
    phpcredits(),
    php_logo_guid(), 
    ini_get(),
    ini_set(), 
    get_loaded_modules(),
    and the section on Predefined
    Variables.