Delphi Language Guide Delphi for Microsoft Win32 Delphi for the Microsoft. Net framework

Character Pointers
The fundamental types PAnsiChar and PWideChar represent pointers to AnsiChar and WideChar values,
respectively. The generic PChar represents a pointer to a Char (that is, in its current implementation, to an AnsiChar).
These character pointers are used to manipulate null-terminated strings. (See Working with null-terminated strings.)
Type-checked Pointers
The 
$T
 compiler directive controls the types of pointer values generated by the @ operator. This directive takes the
form of:
{$T+} or {$T-}
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In the 
{$T-}
 state, the result type of the @ operator is always an untyped pointer that is compatible with all other
pointer types. When @ is applied to a variable reference in the 
{$T+}
 state, the type of the result is 
^T
, where 
T
 is
compatible only with pointers to the type of the variable.