How can I access a user-defined Xcode build setting?

Question

If I added a user-defined setting in my build configuration, how can I read that setting in my Objective-C code?

I have two files in my project, debug.plist and release.plist. I want my MainApp.m file to read one of these files based on which build configuration is running. I set up a user-defined setting named "filename" in both the Debug and Release configurations to point to the appropriate file. But I don't know how my MainApp.m file can read the filename variable from the current running configuration.

zmippie · Answer 1 · 2011-06-17T15:03:17.083

48

Here's what I did, I'm not 100% sure if this is what you're after:

Go into the build Settings panel and choose the gear icon in the bottom left: add User-Defined Setting
Create your user defined setting, for example:
```
MY_LANG -> en_us
```
Then, in the Preprocessor Macro's setting, you can reference that value:
```
LANGCODE="$(MY_LANG)"
```

Now you can refer to LANGCODE in all your source files, and it will be whatever you filled out in your custom build setting. I realize that there's a level of indirection here, but that is intentional in my case: my XCode project contains a bunch of different targets/configurations with their own preprocessor macro's. I don't want to have to go into all of those, just to change the language code. In fact, I define the language code on the project level. I also use MY_LANG in a couple scripts, so just a preprocessor macro wouldn't do. There may be a smarter way, but this works for me.

edited Jun 17 '11 at 15:03

answered Jun 17 '11 at 14:57

zmippie

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ok, I can follow the first two steps, however I cannot figure out what you mean by Preprocessor Macro setting in step three. I tried adding it to the GCC_PREPROCESSOR_DEFINITIONS as described in http://stackoverflow.com/questions/367368/how-to-define-a-preprocessor-symbol-in-xcode however that did not work – gebirgsbärbel Sep 06 '12 at 15:31
6

Another way of doing this is after you created a user setting, go to Build Phases tab, and for the source file where the setting is intedend to be read, add: `-D'LANGCODE=@"$(MY_LANG)"'`. – Aleks N. Oct 25 '12 at 11:27
4

If you define macro for a **string** in the build settings, don't forget to escape quotes like this `LANGCODE=@\"$(MY_LANG)\"` – DanSkeel Jan 18 '18 at 10:32
1

This worked for me in Build Settings for a revision that needs to be a string: `VERSION_REV=\"000000\"` Thanks to @DanSkeel for his note as that helped. – RobLabs Oct 01 '21 at 21:30

AndyDeveloper · Answer 2 · 2020-06-24T15:05:09.417

43

You can access your user-defined build setting at run-time (as suggested in a comment by @JWWalker)

Add an entry to your Info.plist file, and set it to your User-defined Build Setting
```
MySetting -> ${MYSETTING}
```

Read its value from code

Objective-C

[[NSBundle mainBundle] objectForInfoDictionaryKey:@"MySetting"];

[Edit] Swift

guard let mySetting = 
  Bundle.main.object(forInfoDictionaryKey: "MySetting") as? String 
    else { print("MySetting not found") }

edited Jun 24 '20 at 15:05

answered Feb 16 '17 at 02:48

AndyDeveloper

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Is there a way to access the user-defined setting without adding an entry to Info.plist? – Vinicius Bazanella Aug 18 '22 at 12:41

score 23 · Answer 3 · edited Jun 15 '21 at 21:36

23

Swift 4

Lets say "filename" is the String you need in your app.

Add filename=YOUR_STRING to user-defined setting(for debug and release).

And add filename = $(filename) to info.plist.

Then in Swift code:

if let filename = Bundle.main.infoDictionary?["filename"] as? String {
    // do stuff with filename
} 
else {
    // filename wasn't able to be casted to String
}

edited Jun 15 '21 at 21:36

Ethan Allen

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answered Sep 20 '18 at 21:40

Kristian

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This works! Swift 4.2 (Xcode 10.0). Don't forget second step with Info.plist as I did. – jcislinsky Oct 26 '18 at 08:29
Works, so far the simplest solution I found. – River2202 Nov 28 '18 at 22:26
Excellent approach. Works great and is by far the most Swift friendly solution! – metatheoretic Nov 30 '18 at 21:52
1

You really shouldn't for force casting to a String here. I changed the code to make it an optional with else statement. – Ethan Allen Jun 15 '21 at 21:31
I used if-let here, but guard-let works too. – Ethan Allen Jun 15 '21 at 21:38

JWWalker · Answer 4 · 2010-10-19T21:18:31.320

9

Your code can't read arbitrary build settings. You need to use preprocessor macros.

EDIT: For example, in the target settings for the Debug configuration, you could add DEBUGGING=1 in the Preprocessor Macros build setting, and not define DEBUGGING in the Release configuration. Then in your source code you could do things like:

#if DEBUGGING
  use this file
#else
  use the other one
#endif

edited Oct 19 '10 at 21:18

answered Oct 19 '10 at 16:26

JWWalker

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Thanks, JWWalker, can you show me how to define a preprocessor macros specifically for xcode project? – The Lazy Hiker Oct 19 '10 at 17:01
OK, I added an example to my answer. – JWWalker Oct 19 '10 at 21:19
4

P.S. There is one way to use a user-defined setting: Check "Expand Build Settings in Info.plist File", then you can use `$MYSETTING` in the Info.plist file. – JWWalker Oct 19 '10 at 21:36

score 6 · Answer 5 · answered Sep 10 '13 at 13:11

6

I tried zmippie suggestion but it didn't work for me.

I got it working with this:

${MY_LANG}

answered Sep 10 '13 at 13:11

Morten Holmgaard

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score 0 · Answer 6 · answered Sep 12 '17 at 16:38

In case anyone else is still stuck looking for how to do preprocessor macros, look for the Apple LLVM - Preprocessing section in Build Settings. Under it, you will see a section called Preprocessor Macros.

This is where by default, Xcode inserts the DEBUG=1 macro for the debug build configuration.

You can add your own here, and give them different values for debug, release and any custom build configs you may have.

To add one, double-click on the current value list for the config you want, and it'll display a nice little editor with one macro on each line. Just add your own macro name, and give it a value the same way the DEBUG one is done.

These can be checked during the preprocessor build phase using #if, #ifdef etc. to provide conditional code or values.

Hope that helps.

How can I access a user-defined Xcode build setting?

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