The mod load order as well as script module order 3_Game -> 4_World -> 5_Mission can influence which define is present at which time. In my experience defines work as intended if used correctly. Do you have a minimal example setup where it sometimes works and sometimes does not?

For example from yesterday updated of MuchCarKey I cannot detect this mod in my Carcover. But Helkiana using in his mod same method, just create common folder, which is every time loaded. Before yesterday update of his mod all working smooth.

I am test on 1.12 version this with:

1. Client-server mod breachingcharge with block define
2. Only server mod with my code and if def

If i am don't add a 'requiredaddon' #ifdef is not worked, but with added 'requiredaddon' as 'breachingcharge' it is worked ;)

Experimenting today and looks like required addons acts as soft depedency, when requied addon is not present server start without complains. When wants see defines from other mod, must add it to required addons and the are these defines recognized in my mod.

Hmm looks like it works this way only on my local server :/

@MarioE

You should have MOD A and MOD B work separately.
Then when someone wants to use MOD A and MOD B, they should be using a different version which is compatible or a optional add-on version.

You cannot insure a load order without a requiredaddons, so that means you would have to have #ifdef written into both mods.
So for example MOD A would have a #IFDEF MOD_B and MOD B would have #IFDEF MOD_A and then compatibility code.

In Carcover

#IFDEF MuchCarKey
// Code to make compatible
...

in MuchCarKey

#IFDEF Carcover
// code to make comaptibel
...

1.16 again break something which worked before

In much car key mod is inside separate pbo is

#define MuchCarKey

and in Carcover mod I am using

		#ifdef MuchCarKey
		if (!ctx.Read(m_CCIsCKLocked))
			return false;
		
		if (!ctx.Read(m_CCHasCKAssigned))
			return false;
		
		if (!ctx.Read(m_CCCarKeyId))
			return false;
		
		if (!ctx.Read(m_CCCarScriptId))
			return false;
		#endif

That worked more than one year and now is broken. Any idea why ?

maybe only capital letters in name of variable?

hmm #ifdef TRADER also not found it now in 1.16

@Hunterz can you show your root config.cpp

The #define MuchCarKey is in "your" CarCover/Scripts/Common?

Second thing, I'm not sure the #ifdef work in the .cpp file (but maybe I'm wrong

no #define MuChCarKey is in Much Car Key mod, this way my mod detecting if much car key mod is present or not

Ok but you have to add the path to the #define MuChCarKey in your gameScriptModule / worldScriptModule / missionScriptModule (depending where you need it - I usually add the path in each one to be sure) to be able to find it.

sorry but you probably not understand how it works - that #define is defined in Much Car Key mod and I am only detecting using this preprocesor variable if mod is present or not in my mod

and that detection using #ifdef just stopped working again in 1.16

yes I understand, I often use #define and nerver had problem.
Here is an example of mission path list of my PvZmoD Customisable Zombie that need to detect Dayz_Dog or my other PvZmoD:

class missionScriptModule
			{
				value = "";
				files[] = 
				{
					"Dayz_Dog/Scripts/Common",
					"PvzPanelManager/Scripts/Common",
					"LIVEN/PvZmoD_TheDarkHorde/Scripts/Common",
					"LIVEN/PvZmoD_Spawn_System/Scripts/Common",
					"LIVEN/PvZmoD_CustomisableZombies/Scripts/Common",
					"LIVEN/PvZmoD_CustomisableZombies/Scripts/5_Mission"
				};
			};

And remember I'm talking about #ifdef in the .c file, I'm not sure they work well in the .cpp

Ahaa you looking in your mod for specific folders from others mods too

interesting, I will try that

I really think it's how it 's supose to work

Thanks for hint, I will try modify my config according yours example

Note that I posted a little tuto about #defines on the official forum few days ago :
https://forums.dayz.com/topic/252259-good-modding-practice-add-a-define-to-the-scripts-to-help-other-modders-to-fix-conflicts/

If adding the right path solved your problem can you look at the tuto and tell me if it is clear enough (English is not my natural language)

Oh, many thanks for yours hint, now I am able detect MCK, I did that change in my config.cpp

		class defs
		{
			class gameScriptModule
			{
				value="";
				files[]=
				{
					"MuchCarKeyDefines/scripts/Common",
					"TM/Trader/scripts/defines",
					"CarCover/Scripts/Common",
					"CarCover/scripts/3_Game"
				};
			};
			class worldScriptModule
			{
				value="";
				files[]=
				{
					"MuchCarKeyDefines/scripts/Common",
					"TM/Trader/scripts/defines",
					"CarCover/Scripts/Common",
					"CarCover/Scripts/4_World"
				};
			};
			class missionScriptModule
			{
				value="";
				files[]=
				{
					"MuchCarKeyDefines/scripts/Common",
					"TM/Trader/scripts/defines",
					"CarCover/Scripts/Common",
					"CarCover/Scripts/5_Mission"
				};
			};