6.20 Special Parameters

• Untyped reference parameters can be denoted by

  procedure Foo (var x);

  like in Borland Pascal. In GNU Pascal, you can also use

  procedure Foo (var x : Void);

• GNU Pascal defines ellipsis parameters for variable argument lists:

  procedure Foo (a : Integer; ...);

  However, GPC does not (yet) provide a portable mechanism to access the additional arguments.

• Structured function return values: According to Extended Pascal, GNU Pascal allows functions to return records and arrays.

• BP style open array parameters

  procedure Foo (a : array of Integer);

  are implemented. However, Standard Pascal `conformant array parameters' are usually a cleaner mechanism to pass arrays of variable size.

• Besides BP compatible procedural types and procedure pointers (see section 6.15 BP Procedural Types), GNU Pascal supports Standard Pascal's procedural parameters:

  procedure DrawGraph (function f (x : Real) : Real);