Linker Error - CreateMainApp __EXPECTED_EXACTLY_ONE_VR_MAIN_APP_STATEMENT__ with Cardboard SDK

Question

I am developing a Google Cardboard application and building perfectly in iOS. But adding Soomla to the project causes a linker error:

Ld /Users/foundway/Library/Developer/Xcode/DerivedData/Unity-iPhone-grxtfxrygreysieuyeovxlhlmgxu/Build/Intermediates/Unity-iPhone.build/Release-iphoneos/Unity-iPhone.build/Objects-normal/armv7/RealiteerCore normal armv7 cd /Users/foundway/GitHub/RealiteerCore/Build/RealiteerCoreIOS export IPHONEOS_DEPLOYMENT_TARGET=6.0 export PATH="/Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/usr/bin:/Applications/Xcode.app/Contents/Developer/usr/bin:/usr/bin:/bin:/usr/sbin:/sbin" /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/clang++ -arch armv7 -isysroot /Applications/Xcode.app/Contents/Developer/Platforms/iPhoneOS.platform/Developer/SDKs/iPhoneOS8.4.sdk -L/Users/foundway/Library/Developer/Xcode/DerivedData/Unity-iPhone-grxtfxrygreysieuyeovxlhlmgxu/Build/Products/Release-iphoneos -L/Users/foundway/GitHub/RealiteerCore/Build/RealiteerCoreIOS -L/Users/foundway/GitHub/RealiteerCore/Build/RealiteerCoreIOS/Libraries -L/Applications/Unity/Unity.app/Contents/PlaybackEngines/iOSSupport/Trampoline/Libraries -L/Users/foundway/GitHub/RealiteerCore/Assets/Plugins/iOS -F/Users/foundway/Library/Developer/Xcode/DerivedData/Unity-iPhone-grxtfxrygreysieuyeovxlhlmgxu/Build/Products/Release-iphoneos -filelist /Users/foundway/Library/Developer/Xcode/DerivedData/Unity-iPhone-grxtfxrygreysieuyeovxlhlmgxu/Build/Intermediates/Unity-iPhone.build/Release-iphoneos/Unity-iPhone.build/Objects-normal/armv7/RealiteerCore.LinkFileList -Xlinker -map -Xlinker /Users/foundway/Library/Developer/Xcode/DerivedData/Unity-iPhone-grxtfxrygreysieuyeovxlhlmgxu/Build/Intermediates/Unity-iPhone.build/Release-iphoneos/Unity-iPhone.build/RealiteerCore-LinkMap-normal-armv7.txt -dead_strip -lc++ -weak_framework CoreMotion -weak-lSystem -ObjC -stdlib=libc++ -fobjc-arc -fobjc-link-runtime -miphoneos-version-min=6.0 -framework Security -framework CoreText -framework Foundation -framework UIKit -framework OpenGLES -framework QuartzCore -framework OpenAL -liconv.2 -framework AudioToolbox -framework CFNetwork -framework MediaPlayer -framework CoreLocation -framework SystemConfiguration -weak_framework iAd -framework CoreMedia -framework CoreVideo -weak_framework AVFoundation -framework CoreGraphics -weak_framework CoreMotion -liPhone-lib-il2cpp -liontext -lVuforia -lcardboard -lionimagecompression -lionimage -lremote_assets -lport -levent_internal -lQuantumCore -lbase -lNimbusCore -lrecorder -liongfx -lprotos_lib -lsoftware -lionwebp -lcardboard_protos -lionportgfx -lionstblib -lGoogleKitHUD -lionmath -lionlodepnglib -liongfxutils -lsensors -ltype -lapi -lprotobuf -lionfreetype2 -lionremote -lNimbusAttributedLabel -llogging -lProtocolBuffers -lUnityiOSProfile -lplatform -lSoomlaIOSCore -lvr -lionport -lcomposite -ldatatypes -ldevice -lNimbusModels -levent -lionanalytics -lgflags -lQCARUnityPlayer -lionbase -lionjsoncpp -lionzlib -ldevice_internal -lionmongoose -lGoogleKitCore -lionopenctm -lvrunity -lSoomlaiOSProfile -lUnitySoomlaiOSCore -llogging_protos -lionprofile -lsqlite3.0 -Xlinker -dependency_info -Xlinker /Users/foundway/Library/Developer/Xcode/DerivedData/Unity-iPhone-grxtfxrygreysieuyeovxlhlmgxu/Build/Intermediates/Unity-iPhone.build/Release-iphoneos/Unity-iPhone.build/Objects-normal/armv7/RealiteerCore_dependency_info.dat -o /Users/foundway/Library/Developer/Xcode/DerivedData/Unity-iPhone-grxtfxrygreysieuyeovxlhlmgxu/Build/Intermediates/Unity-iPhone.build/Release-iphoneos/Unity-iPhone.build/Objects-normal/armv7/RealiteerCore Undefined symbols for architecture armv7: "gvr::CreateMainApp__EXPECTED_EXACTLY_ONE_VR_MAIN_APP_STATEMENT__(std::__1::vector<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >, std::__1::allocator<std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > > > const&)", referenced from: l001 in libplatform.a(vr_ios.o) ld: symbol(s) not found for architecture armv7 clang: error: linker command failed with exit code 1 (use -v to see invocation) 

I just added Soomla to my Cardboard application, but it looks like Soomla and Google Cardboard are fighting for the main application (libplatform.a - from Google Cardboard). I believe that Google Cardboard should be the main application.

So, I am wondering if there are ways to make other plugins not fight for the main application?

It could be something else ... Above my theory.

Answer 1

This is due to the Xcode -ObjC build flag, which changes the way the .a files are linked. There is some code in the Cardboard .a files that are not needed (or not needed) by the cardboard SDK itself (for example, CreateMainApp).

You can fix this by removing the -ObjC flag from link flags in Xcode. Note: this may result in Soomla not being connected, but hopefully they only included it “just in case”. So try this first, and if it still doesn't work, please comment here.

Answer 2

I faced the same exact problem with Soomla SDKs and cardboard, I believe that your theory is correct, Soomla wants to be the main application, but why is this needed? Is there any work? Help us Somalia !!!

I tried to hide the project one SDK at a time, it is definitely related to the somla or maybe FB sdk (since soomla also controls this functionality)

symbols for arm64 architecture: "gvr :: CreateMainApp__EXPECTED_EXACTLY_ONE_VR_MAIN_APP_STATEMENT __ (std :: __ 1 :: vector, std :: __ 1 :: allocator>, std :: __ 1 :: allocator, std :: __ 1 :: allocator →> const &) "referenced by: