Delphi Error – E2079 Procedure NEW needs constructor

Delphi Compiler Error

E2079 Procedure NEW needs constructor

Reason for the Error & Solution

This error message is issued when an identifier given in the parameter list to New is not a constructor.

program Produce;

type
  PMyObject = ^TMyObject;
  TMyObject = object
  F: Integer;
  constructor Init;
  destructor Done;
  end;

constructor TMyObject.Init;
begin
  F := 42;
end;

destructor TMyObject.Done;
begin
end;

var
  P: PMyObject;

begin
  New(P, Done);              (*<-- Error message here*)
end.

By mistake, we called New with the destructor, not the constructor.

program Solve;

type
  PMyObject = ^TMyObject;
  TMyObject = object
  F: Integer;
  constructor Init;
  destructor Done;
  end;

constructor TMyObject.Init;
begin
  F := 42;
end;

destructor TMyObject.Done;
begin
end;

var
  P: PMyObject;

begin
  New(P, Init);
end.

Make sure you give the New standard function a constructor, or no additional argument at all.