Using "Conditional Compilation"

Posted on 2014-03-15
Last Modified: 2014-03-16
Hi, I got a little info googling around on "Conditional Compilation" for Delphi, and I now know just enough to be dangerous with it. It seems like it will be very convenient and save me from having to keep two versions of my source code - one for demo, and one for full version. My question is - when I turn on a conditional compiler directive like this from the FormCreate procedure of my main form:


... is it "global" over all the forms and units of my app? Just doing a quick test here, it seems not. Is there some way where I only have to make my 'Define' statement once (like in the project .dpr file maybe?) and it will be global for all the forms in my project... or do I have to explicitly specify the {$Define DEMOMODEON} directive in the FormCreate event for each of my forms/units?

Question by:shawn857
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LVL 31

Expert Comment

by:Marco Gasi
ID: 39931863
No, it isn't global, you have to define your condition in each form.
LVL 31

Expert Comment

by:Marco Gasi
ID: 39931871
But you don't have to define that in the FormCreate event. Just put it in your implementation section after the uses clause
unit Unit1;


  Windows, Messages, SysUtils, ... ;


  TGetVersion = function (AppName: PChar): PChar;

  TForm1 = class(TForm)
    { Private declarations }
    { Public declarations }

  Form1: TForm;


uses someunit;


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LVL 26

Accepted Solution

Sinisa Vuk earned 300 total points
ID: 39931904
You can set global for all forms in different .dproj (one for release, demo, ...)
Add  DEMOMODEON in Projects Options/Directories-Conditionals/Conditional defines...
(separate it with ';')
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Author Comment

ID: 39932111
Thank you both. Sinisa - I use Delphi 7, I don't think I have this capability for .dproj files? This is only for D2007 and upwards?

LVL 31

Expert Comment

by:Marco Gasi
ID: 39932236
You have for .dpr files in the same Project Options panel: Main menu Project -> Options ->Directorues/Conditionals/Conditional defines

@sinisav The beauty to be here in EE is that I always learn somthing more: I every used writing define in the code... And now I have a doubt: could I put gobal define writing directly in the project source?

Author Comment

ID: 39932240
Yes I would like to know this too Marco! How is it done?

LVL 31

Assisted Solution

by:Marco Gasi
Marco Gasi earned 200 total points
ID: 39932246
If you click Project menu, you can choose View source: there you can write code to manage splashes creens, for instance. Well, there I think you can write your global defines immediately after the first line with the project name, project Project1.

I'm not sure, but you can give it a try to see if a define there is global and saw by all forms...
LVL 26

Expert Comment

by:Sinisa Vuk
ID: 39932970
Common usage is to use "include" file where those "defines" are defined. Then include this file ( {$I} ) to all forms/units where you want to use conditionals.

Author Closing Comment

ID: 39933500
Thank you both Sinisa and Marco for your responses. Indeed, in the Project|Options|Directories/Conditionals tab next to "Conditional Defines", a few simple tests revealed a very nice solution for me: I have two conditions I must have for my app:

DEMOMODEON   (demo version of my app, some features crippled)
SECURITYON        (version of my app where I add the 3rd party security anti-cracking module... undebuggable from the IDE in this state)

Using these two switches, I can have 4 different EXE files:

(1) Non-final version of my app (ie. debuggable) in full-feature mode (no switches turned on)
(2) Non-final version of my app (ie. debuggable) in DEMO mode (only DEMOMODEON turned on)
(3) Final version of my app (ie. not debuggable, with security module) in full-feature mode (only SECURITYON turned on)
(4) Final version of my app (ie. not debuggable, with security module) in DEMO mode (both SECURITYON and DEMOMODEON turned on).

This is fantastic! I don't need to maintain 4 different source codes - only one! All I needed to do was add 3 items in the "Conditional Defines" area mentioned above:


Then I can choose one, or none of these for whatever appropriate "mode" I choose to compile... fantastic!


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