Making C plugins work in Android. Just not happening.

Hello all,

So I was checking out unity's native plugin documentations. I am trying to call a C function from c# code by my c plugin. I downloaded this example

https://docs.unity3d.com/uploads/Examples/AndroidNativePlugin.zip

This one works as expected when you build with IL2CPP scripting backend. Now I tried to add more function in Nativecode.c file. Now it looks somewhat like this:

Code (CSharp):

1. float add(float x, float y)
2. {
3.     return (x+y);
4. }
5.  
6. float minus(float x, float y)
7. {
8.     return (x-y);
9. }

I complied a new libnative.so file replacing existing one. But I am getting below error:

DllNotFoundException: Dll file "native" could not be loaded.

What is it that I am missing here?

 

Above is full source code of NativeCode.c file.

There are other three files along with .c file and it's content.

Android.mk:

Code (CSharp):

1. include $(CLEAR_VARS)
2.  
3. # override strip command to strip all symbols from output library; no need to ship with those..
4. # cmd-strip = $(TOOLCHAIN_PREFIX)strip $1
5.  
6. LOCAL_ARM_MODE  := arm
7. LOCAL_PATH      := $(NDK_PROJECT_PATH)
8. LOCAL_MODULE    := libnative
9. LOCAL_CFLAGS    := -Werror
10. LOCAL_SRC_FILES := NativeCode.c
11. LOCAL_LDLIBS    := -llog
12.  
13. include $(BUILD_SHARED_LIBRARY)

Application.mk:

Code (CSharp):

1. APP_OPTIM        := release
2. APP_ABI          := armeabi
3. APP_PLATFORM     := android-8
4. APP_BUILD_SCRIPT := Android.mk

build_plugin.sh:

Code (CSharp):

1. #!/bin/sh
2. echo ""
3. echo "Compiling NativeCode.c..."
4. $ANDROID_NDK_ROOT/ndk-build NDK_PROJECT_PATH=. NDK_APPLICATION_MK=Application.mk $*
5. mv libs/armeabi/libnative.so ..
6.  
7. echo ""
8. echo "Cleaning up / removing build folders..."  #optional..
9. rm -rf libs
10. rm -rf obj
11.  
12. echo ""
13. echo "Done!"

And the command I used to generate .so file:

Code (CSharp):

1. gcc *.c -O3 -fPIC -shared -o libnative.so

 

No I used this command from my system gcc. How do I set up android NDKs gcc? I also tried executing sh file but it didn't created compiled libnative.so file.

 

Thanks a lot. Now it's working as expected