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### Null

#### Synopsis

         var
           Null: Void absolute 0;

#### Description

`Null` is a predefined variable at address `nil`. `Null` can be passed as a “void” argument to a procedure, function or operator expecting a “var” parameter. Note: Make sure they can handle this case, otherwise this is likely to cause an exception and the program will be terminated. Since `Null` is an L-value, it can be taken as “nil-reference”.

#### Conforming to

`Null` is a Borland Delphi extension.

#### Example

         program NullDemo;
         type
           PString = ^String;
         var
           Com1: String (25) = 'This is an amazing number';
           Com2: String (25) = 'This is a boring number';

         procedure FooBar (Foo: Integer; var Comment: PString);
         begin
           if Odd (Foo) then
             WriteLn ('FooBar:', Foo, ' is odd')
            else
             WriteLn ('FooBar:', Foo, ' is even');
           if @Comment <> nil then
             if not Odd (Foo) then
               Comment := @Com1
             else
               Comment := @Com2
         end;

         var
           S: String (25);
           P: PString value @S;

         begin
           { FooBar allows you to leave out variables
             for any information you might not need }
           FooBar (1, Null);
           { But FooBar is flexible, after all }
           FooBar (6, P);
           WriteLn ('FooBar said about 6: `', P^, '''')
         end.

#### See also

nil