former worked code does not work

Question

There are code below and worked well before

unit Unit1;
  {$DEFINE _Full}
 // {$DEFINE _Trial}

interface

uses Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms;


{$ifdef  _Trial}

_programname='abc';


{$endif}

{$ifdef  _Full}

_programname='abc';


{$endif}

but today I run Delphi and try to compile, it reported

Identifier redeclared: '_programname'

it looks like

  {$DEFINE _Full}

does not work

your comment welcome

Answer 1

Both conditionals are defined. That can be inferred from the compiler error.

Either single line // comments do not comment out defines. Or you are defining _Trial at the project level. To the very best of my knowledge, a single line // comment will comment out a directive. So I presume that _Trial is defined at the project level.

The idiomatic way to comment out defines is like this:

{.$DEFINE _Trial}

For an either or condition it might be simpler with a single conditional:

{$IFDEF _Trial}
  .... stuff for trial version
{$ELSE}
  .... stuff for full version
{$END}

All that said, perhaps your actual problem is different because the code you show does not match the error message you reported. I'd expect an error saying that a keyword was expected, but identifier _programname found. The code in the question appears to omit the const keyword before the declaration of _programname.