%php.ini% directives are defined using the %<phpini>% tag. To define a %php.ini% directive you have to specify its %name%, %type% and default %value%. Valid directive %name% values are C variable names. The actual directive name is the extension name followed by a single dot '.' and the specified name. A directive may be of %type% %bool%, %int%, %float% or %string%. Directive default values are passed to the engine as strings, so you may not use any C constants or preprocessor macros here. The default value strings are parsed by the %OnUpdate% handler registered for that directive. The %OnUpdate% handler defaults to the appropriate internal %OnUpdate...% handler for its %type% unless you specify a different handler using the %onupdate% attribute. The directive value may be changed at any time unless you specify an %access% attribute. Possible values are %all% (default), %perdir% (may be changed by local %.htaccess% file but not by PHP code) and %system% (may only be set in %php.ini% or global web server configuration. The content data of %<phpini>% tags is used to generate documentation for the defined directive.