Qt + firebase C++ SDK linking issues on iOS

[kuzulis]

Hi all,

I have following build env:

• host: OSX 10.12 Sierra
• XCode 9.2
• Qt 5.10.1 for iOS
• QtCreator 4.7.0
• firebase 5.2

and try to build my application from QtCreator for iOS with the firebase support, but it fails with following linking errors:

Undefined symbols for architecture arm64:
  "_OBJC_CLASS_$_FIRMessaging", referenced from:
      objc-class-ref in firebase_messaging(messaging_231c52c311096cfce13e67fa91eb9ac5.o)
  "_OBJC_CLASS_$_FIRApp", referenced from:
      objc-class-ref in firebase(app_ios_814e1620d4f88024cea4bade26623a67.o)
  "_OBJC_CLASS_$_FIROptions", referenced from:
      objc-class-ref in firebase(app_ios_814e1620d4f88024cea4bade26623a67.o)
ld: symbol(s) not found for architecture arm64
clang: error: linker command failed with exit code 1 (use -v to see invocation)

I have simplified my project to following code:

== main.cpp ==

#include <QCoreApplication>

#include <firebase/app.h>
#include <firebase/messaging.h>
#include <firebase/util.h>

int main(int argc, char *argv[])
{
    QCoreApplication a(argc, argv);
    ::firebase::App *fapp = ::firebase::App::Create();
    Q_UNUSED(fapp);
    return a.exec();
}

and a project file is:

QT -= gui
CONFIG += c++11 console
CONFIG -= app_bundle

# Check for GOOGLE_FIREBASE_SDK environment variable.
ENV_GOOGLE_FIREBASE_SDK = $$(GOOGLE_FIREBASE_SDK)
# Or define GOOGLE_FIREBASE_SDK path here.
GOOGLE_FIREBASE_SDK =

isEmpty(ENV_GOOGLE_FIREBASE_SDK) {
    isEmpty(GOOGLE_FIREBASE_SDK) {
        message("GOOGLE_FIREBASE_SDK" environment variable not detected!)
    }
}

INCLUDEPATH += $$(GOOGLE_FIREBASE_SDK)
INCLUDEPATH += $$(GOOGLE_FIREBASE_SDK)/include

SOURCES += \
        main.cpp

FCM_LIBS_PATH = $$(GOOGLE_FIREBASE_SDK)/frameworks/ios/universal
message("FCM_LIBS_PATH = $$FCM_LIBS_PATH")

LIBS += -F$$FCM_LIBS_PATH \
   -framework firebase_messaging \
   -framework firebase \
   -framework Foundation \
   -framework UserNotifications \
   -framework UIKit \
   -framework CoreGraphics

The firebase SDK contains different frameworks directories for different architectures :

• ~/firebase_cpp_sdk/frameworks/ios/universal
• ~/firebase_cpp_sdk/frameworks/ios/amd64
• ~/firebase_cpp_sdk/frameworks/ios/i386
• ~/firebase_cpp_sdk/frameworks/ios/x86_64
• ~/firebase_cpp_sdk/frameworks/ios/armv7

As I see that error related to 'arm64' architecture, so, I have changed the project file LIBS to use 'arm64' instead of 'universal', but this does not help.

Also I tried to build the project from the XCode, using qmake's generated xcode.project file, but there are same error.

I looked on stackoverflow similar issues, but that workarounds does not help:

1. I tried to remove the /Users/admin/Library/Developer/Xcode/DerivedData directory.
2. I tried to play with the XCode options "Build Settings -> Build Active Architecture Only -> <yes/no>"

I looked a code from the following projects:

• qtcloudmessaging: https://github.com/qt/qtcloudmessaging
• QtFirebase: https://github.com/Larpon/QtFirebase

But I don't understand why this linker error happens.. Maybe is it a qmake bug?

[pets]

I cannot help you with the problem but here Firebase works without problems. Have you tried to run qmake again, or delete the generated files?

[kuzulis]

but here Firebase works without problems

Where is "here" ?