# extension

The attribute is specified by the user.

In TITAN the following three arguments are specified:.

- internal
  is appended to the port type definition if all instances of a TTCNâ3 port type are intended to be used for internal communication only (i.e. between two TTCNâ3 test components).

- address
  is appended to the port type definition if the user wants to use address values in TTCNâ3 port operations.

- done
  is appended to a function with runs on clause if the return value of that function must be retrieved after the corresponding component was stopped.

Related keywords:

- with
- override

### extension [ override ] [ (qualifier) ] "argument"

- the optional override directive forces all contained types at all lower scopes to be forced to the specified attribute.

- the optional qualifier points out the entity for which the argument is valid.

- argument is a free-text string specifying the actual attribute.

Example:

type port Vnitrni_PT message { inout octetstring } with { extension "internal"}

The port called Vnitrni_PT both sends and receives octetstrings and is used for internal communication only.

BNF definition of extension