iOS biometrics, how to create LAContext instance from C++? - c++

Question

I'm trying to implement biometric authentication on iOS from a C++ codebase. Here is one example.
In order to achieve this, I need to use the LAContext obj-c APIs. However, when I try to initialize the class from C++ I get a pointer/reference error:
// Cannot initialize a variable of type 'LAContext *__strong' with an rvalue of type 'LAContext'
LAContext* authContext = LAContext();
Is there any way to achieve this? Or is this struct available from Obj-c only?
Edit 1:
My file is in Obj-C++, so in theory I should be able to mix C++ and Obj-C code, however when I try to write a Obj-C function to alloc the LAContext object I get a missing symbols error:
-(bool)biometricsAvailable {
LAContext *myContext = [[LAContext alloc] init];
NSError *authError = nil;
return true;
}
On the compilation step this error is thrown:
Undefined symbol: _OBJC_CLASS_$_LAContext
XCode itself does not show any error while editing the file, only happens when I try to build/compile the app.

Answer 1

As it turns out, the problem was not with mixing C++ and Obj-C code, but rather with my library being linked via cocoapods and the LocalAuthentication framework being missing.
I needed to add:
s.frameworks = "LocalAuthentication"
to the podspec and creating a LAContext instance works just fine.