The easiest way to create a binding is to create a Xamarin.iOS Binding Project. You can do this from Xamarin Studio on Mac by selecting the project type, iOS Binding Project: 
The easiest way to create a binding is to create a Xamarin.iOS Binding Project. You can do this from Xamarin Studio on Mac by selecting the project type, iOS Binding Project:
The easiest way to create a binding is to create a Xamarin.iOS Binding Project. You can do this from Visual Studio on Windows by selecting the project type, iOS Binding Project: 
[LinkWith] attribute. Solutions:
- [LinkWith] attribute to include the framework it needs: [LinkWith ("mylib.a", Frameworks = "SystemConfiguration")]
- -gcc_flags '-framework SystemFramework' to mtouch (this is done by modifying the additional mtouch arguments in the project's iOS Build options page. Remember that this must be done for every project configuration).[LinkWith] attribute. This is usually fairly easy to recognize, because the symbols have are mangled C++ symbols (one common example is __ZNKSt9exception4whatEv).
- [LinkWith] attribute to set the IsCxx flag: [LinkWith ("mylib.a", IsCxx = true)]
- -cxx to mtouch (this is done by modifying the additional mtouch arguments in the project's iOS Build options page. Remember that this must be done for every project configuration).
- -cxx to mtouch (this is done by modifying the additional mtouch arguments in the project's iOS Build options page. Remember that this must be done for every project configuration).
-[Protocol] attribute in its api definition. Solutions:
- [Protocol] attribute:
- [BaseType (typeof (NSObject))]
-[Protocol] // Add this
-public interface MyProtocol
-{
-}[Protocol] attribute in its api definition. Solutions:
+ - Add the missing `[Protocol]` attribute:
+
+ [BaseType (typeof (NSObject))]
+ [Protocol] // Add this
+ public interface MyProtocol
+ {
+ }
- # Native libraries are usually fat libraries, containing binary code for
- # several architectures in the same file. First we extract the binary
- # code for the architecture we're interested in.
- lipo libNative.a -thin i386 -output libNative.i386.a
- # Now query the native library for the duplicated symbol.
- nm libNative.i386.a | fgrep 'SYMBOL'
+* The same native library is included twice.
+* Two distinct native libraries happen to define the same symbols.
+* A native library is not correctly built, and contains the same symbol more than once.
+ You can confirm this by using the following set of commands from a terminal (replace i386 with x86_64/armv7/armv7s/arm64 according to which architecture you're building for):
- # You can also list the object files inside the native library.
- # In most cases this will reveal duplicated object files.
- ar -t libNative.i386.a # Find out if the library is a fat library, and which
- # architectures it contains.
- lipo -info libNative.a
+ # Now query the native library for the duplicated symbol.
+ nm libNative.i386.a | fgrep 'SYMBOL'
- # Extract each architecture (i386/x86_64/armv7/armv7s/arm64) to a separate file
- lipo libNative.a -thin ARCH -output libNative.ARCH.a
+ # You can also list the object files inside the native library.
+ # In most cases this will reveal duplicated object files.
+ ar -t libNative.i386.a
- # Extract the object files for the offending architecture
- # This will remove the duplicates by overwriting them
- # (since they have the same filename)
- mkdir -p ARCH
- cd ARCH
- ar -x ../libNative.ARCH.a
+ There are a few possible ways to fix this:
- # Reassemble the object files in an .a
- ar -r ../libNative.ARCH.a *.o
- cd ..
-
- # Reassemble the fat library
- lipo *.a -create -output libNative.a[LinkWith] attributes have enabled SmartLink:
-[assembly: LinkWith ("libNative.a", SmartLink = true)]-gcc_flags is passed to mtouch (in the additional mtouch arguments field of the project's iOS Build options).