Delphi in a Nutshell

Name

$TypeInfo Compiler Directive

Syntax

{$M-}           // default
{$TypeInfo Off} // default
{$M+}
{$TypeInfo On}

Scope

Local

Description

When the $TypeInfo directive is enabled, classes are compiled with runtime type information. This means the class can have a published section, and the compiler stores additional information about the class in the class’s virtual method table.

Any class that inherits from a class with RTTI also has RTTI, so you need the $TypeInfo directive only for the base class. Delphi compiles the TPersistent class with $TypeInfo, so all derived classes (including TComponent, TForm, and all the VCL controls and related classes) have RTTI.

See Also

Class Keyword