use of @import when modules are disabled

Question

I have the following import in my code:

@import Foundation;

I am encountering the following build error:

use of @import when modules are disabled

I have seen @import vs #import - iOS 7 and I have set "Enable Modules" to "YES".

Despite this, my problem is not solved.

Your question is surely your answer? I thought that you had to enable modules to be able to use @import? — SunburstEnzo
– SunburstEnzo, Commented Jan 19, 2016 at 9:41
Unfortunately @import is not supported yet for .mm files or rather Objective-C++ (I tested with both g++ and clang++ as I really wanted to make this work). — Top-Master
– Top-Master, Commented Jun 16, 2021 at 16:09

Peter Brockmann · Accepted Answer · 2020-10-26 14:41:03Z

108

I got this warning in a zero-swift project whenever I tried to add the @import SafariServices; statement.

Solution: Enable the modules. Go to the Target > Build Settings and set the Enable Modules (C and Objective-C modules) to YES.

OR

Note: I haven't verified this potential solution, but probably worthy of consideration if there are side effects caused by this solution.

Rather than enabling modules to entire project, we can enable modules for a specific file which is importing c++ file. Go to build phases -> Compile Sources -> Select the file -> Add compiler flag -fmodules

edited Oct 26, 2020 at 14:41

answered Feb 6, 2017 at 0:49

Peter Brockmann

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5 Comments

Josh Over a year ago

Thanks! worked for me. PS: you forgot to censor your target name :-)

Peter Brockmann Over a year ago

Thanks @Josh , much appreciated.

James T Snell Over a year ago

To my amazement, this didn't resolve the matter for me. Then after running out of ideas as I was sure THIS IS right, I restarted Xcode (9.2) and then it worked totally fine. Sigh.

Cerniuk Over a year ago

Xcode 9.3, struggled with same, did same, and happened to read your note Mr. Snell, quit Xcode and opened, and THAT completed the solution. (bad Xcode dog BAD :-)

mark.ed Over a year ago

Thanks Peter - I've been trying to update parse and parse/ui on an old app to move it to sashido and i was banging my head agains the wall that none of the PF stuff was working!

Aleks N. · Accepted Answer · 2016-03-30 11:32:29Z

44

The possible cause is that you use Objective-C++. Then modules get disabled despite the proper build settings.

answered Mar 30, 2016 at 11:32

Aleks N.

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5 Comments

FranticRock Over a year ago

I, at one point had .mm files in the project. They are no longer there. I double checked - no .mm files in project. Also, i have done everything already described in this thread. Still getting the same error. Modules are enabled on all targets. Foundation is imported. I checked the file types on all source files, they are Objective-C, not Objective-C++. Any suggestions?

KarenAnne Over a year ago

I noticed the issue is caused by importing the framework (with @import Foundation) into a .mm file

Lysdexia Over a year ago

I am using Obj-C++, and facing this same problem. What should I do?

Quang Vĩnh Hà Over a year ago

you should create an Obj-C wrapper that use @import (if you actually need to)

Dmitry Kolesnikovich Over a year ago

hundred times this! i removed @import Foundation from MyFramework.h and it works now!

Warren Stringer · Accepted Answer · 2019-02-05 03:43:05Z

28

I've been mixing ObjC, ObjC++, C++, and Metal. Whenever I get the "use of @import when modules are disabled" I try replacing:

@import Name;

with:

#import "Name/Name.h"

example, replace:

@import Metal;
@import MetalKit;
@import CoreVideo;

with:

#import "Metal/Metal.h"
#import "MetalKit/MetalKit.h"
#import "CoreVideo/CoreVideo.h"

It seems to work.

edited Feb 5, 2019 at 3:43

answered Jan 27, 2019 at 10:03

Warren Stringer

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1 Comment

Bruno Bieri Over a year ago

Thanks! Works for me too by replacing @import GoogleMobileAds; with #import "GoogleMobileAds/GADBannerView.h"

Uday Sravan K · Accepted Answer · 2016-09-28 17:45:24Z

14

Check if you are using #import "ProductName-Swift.h" somewhere in .mm files or any other files other than objc files.

Because if you use this import in cpp files then modules gets disabled automatically.

answered Sep 28, 2016 at 17:45

Uday Sravan K

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Comments

Kazuya Gosho · Accepted Answer · 2023-02-25 10:28:10Z

4

If you are using objective-c++ (.mm file) and none of solutions above work, you can try the following:

Open Xcode Build Settings
Targets -> Build Settings -> Apple Clang - Custom Compiler Flags > Other C++ Flags
Add -fcxx-modules flag

then build again. The error should be gone.

Credit: https://developers.karte.io/docs/setup-react-native-sdk-v2

answered Feb 25, 2023 at 10:28

Kazuya Gosho

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