Section 16

### Formal parameters

A _formal parameter list_ specifies what a TTCN-3 language element is

parameterized and which parameters are accepted.

A _formal parameter list_ specifies how a TTCN-3 language element is

parameterized, which parameters are accepted and how parameters are accessed.

**Syntactical Description**

**Semantic description**

The _formal parameter_ declaration adds a new parameter with given _name_ into

A _formal parameter_ declaration adds a new parameter with given _name_ into

the scope of the parameterized language element (see [uniqueness of

identifiers]).

A _formal parameter_ has a static type associated with it.

The type of the parameter shall be specified using a _[type expression]_

and shall not change during its [invocation].

and shall not change during its [lifetime].

A _formal parameter_ may be declared as array by using the [array short-hand

notation].

same _formal parameter list_.

> NOTE: Referencing type-parameters, visible components (e.g. `mtc`, `self`, ...)

> or even variables of the runs-on component is permitted.

> or variables of the runs-on component is permitted.

A _formal parameter_ is either an _in-parameter_, indicated by the `in`

keyword, _inout-parameter_, indicated by the `inout` keyword, or

keyword, an _inout-parameter_, indicated by the `inout` keyword, or

_out-parameter_, indicated by the `out` keyword.

A _formal parameter_ without any of these keywords is considered an

Access to parameters passed by reference (i.e. `inout`) shall dereference implicitly.

A _formal parameter_ gets assigned its value when the parameterized TTCN-3

language element is passed an [actual parameter]; when a function is invoked,

when a template is instantiated, etc.

language element is passed an [actual parameter], i.e. when a function is invoked,

a template is instantiated, etc.

**Restrictions**