CODEWITHSUNDEEP
vhdlfpgaasic
andrsmllr
andrsmllr

Reputation: 1223

How to define default value for record type

Is it possible to define a default value for a record type or generally any user defined type?

Something like (pseudo VHDL):

type t_foo is record
    a : integer := 4;
    b : std_logic := '0';
end record;

or

subtype glarp is integer range 0 to 10 := 5;

EDIT: changed glarp from type to subtype definition.

Upvotes: 4

Views: 3117

Answers (1)

andrsmllr
andrsmllr

Reputation: 1223

I take the liberty of turning a comment into an answer. The initial value for a record type could be defined by a constant of that type.

type t_foo is record
    a : integer;
    b : std_logic;
end record;

constant INIT_T_FOO : t_foo := (a => 4, b => '0');

signal bar : t_foo := INIT_T_FOO;

A downside of this approach is that the user has to ensure the correct initial value is set every time an object of type t_foo is defined. Using a constant to define an initial value can save some typing and makes it easier to change the initial value later. But again, it is not possible to enforce a specific initial value this way, it all comes down to coding discipline and human error, thus it's a suboptimal solution.

Upvotes: 2

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