Develop Reference

How to generate arm64-v8a 64bit shared object from c++ code?

I've been using a c++ library on my android app for some time now but it has been using 32-bit. I'm trying to compile now the c++ library to a 64bit .so file but every time I do ndk-build I do see the armeabi-v7a get generated successfully, but when the arm64-v8a tries to compile, it fails and gives me the following error message:
libfftw3.a: error adding symbols: File in wrong format
collect2: error: ld returned 1 exit status
I'm going to place below my Application.mk and Android.mk respectively to show what I've done to try to do this properly.
Application.mk
APP_STL := gnustl_static
NDK_TOOLCHAIN_VERSION=4.9
APP_CPPFLAGS += -frtti
APP_PLATFORM := android-23
APP_CPPFLAGS += -std=c++11
APP_ABI := armeabi-v7a arm64-v8a
APP_MODULES := SCCpp
Android.mk
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
CXXFLAGS += -arch x86_64 -arch i386
LOCAL_MODULE := fftw3
LOCAL_SRC_FILES := ../lib/libfftw3.a
LOCAL_EXPORT_C_INCLUDES = $(LOCAL_PATH)/..
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
GLOBAL_C_INCLUDES := \
$(LOCAL_PATH)/../src
LOCAL_SRC_FILES += ../src/d/re.cpp
LOCAL_SRC_FILES += ../src/d/me.cpp
LOCAL_SRC_FILES += ../src/d/ev.cpp
LOCAL_SRC_FILES += ../src/d/fe.cpp
LOCAL_SRC_FILES += ../src/fft/fourier.cpp
LOCAL_SRC_FILES += ../src/nu/ac.cpp
LOCAL_SRC_FILES += ../src/nu/st.cpp
LOCAL_SRC_FILES += ../src/utils/converter.cpp
LOCAL_SRC_FILES += ../src/sci.cpp
LOCAL_MODULE := SCCpp
LOCAL_MODULE_FILENAME := libSCCpp
LOCAL_STATIC_LIBRARIES := fftw3
LOCAL_CPP_FEATURES += exceptions
LOCAL_CFLAGS += -fopenmp
LOCAL_CFLAGS += -Ofast
LOCAL_LDFLAGS += -fopenmp -t
LOCAL_CPPFLAGS := -std=c++11
LOCAL_LDLIBS += -latomic -llog
LOCAL_C_INCLUDES := $(GLOBAL_C_INCLUDES) $(LOCAL_PATH)/../../../3rdParty/fftw-3.3.4-dll32/
LOCAL_EXPORT_CPPFLAGS := -fexceptions -frtti
include $(BUILD_SHARED_LIBRARY)
I'm really unfamiliar with this whole process so I'm at a dead end especially since the logs don't really tell me anything at all. I thought that by just adding in the arm64-v8a would automatically generate the 64bit shared object. Is there a missing step?
If there's any missing information that I should provide, please ask in the comments so I can give more details, but as of now in my current position, this is all that I have touched in the code base for the c++ library so I'm not quite sure where all the pieces are at the moment.

You use a prebuilt library at
../lib/libfftw3.a
You must build fftw3 for arm64, too. Usually we have
LOCAL_SRC_FILES := ../lib/$(TARGET_ARCH_ABI)/libfftw3.a
so that ndk-build can choose the right variant of the 3rd party lib.
The instructions to build fftw3 for arm64 are available on GitHub.

Android Studio 2.2.1 NDK Error:Cannot get property 'soFolder' on null object

I tried to link my existing NDK C code with the new Android Studio 2.2.1 from the relevant Link C++ Project with Gradle menu but I'm getting the following error:
Error:Cannot get property 'soFolder' on null object
I really have no idea what is causing this error as my native code used to work fine in previous Android Studio versions.
Currently my app-specific gradle file looks like this
In addition here are my mk files:
Android.mk
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
include $(LOCAL_PATH)/android-config.mk
LOCAL_CFLAGS := -DNO_WINDOWS_BRAINDEATH -DOPENSSL_BN_ASM_MONT -DSHA1_AS
ifeq ($(TARGET_ARCH),arm)
LOCAL_CFLAGS :=$(LOCAL_CFLAGS) -march=armv6
LOCAL_SRC_FILES := sha/sha1-armv4-large.S
endif
ifeq ($(TARGET_ARCH),x86)
LOCAL_CFLAGS :=$(LOCAL_CFLAGS) -msse2 -m32 -march=i686 -mtune=atom
LOCAL_SRC_FILES := sha/sha1-586.S
endif
ifeq ($(TARGET_ARCH),mips)
LOCAL_CFLAGS :=$(LOCAL_CFLAGS) -march=mips1
LOCAL_SRC_FILES := sha/sha1-mips.S
endif
LOCAL_SRC_FILES := $(LOCAL_SRC_FILES) \
sha/sha1dgst.c \
nativecalc.c \
LOCAL_C_INCLUDES := $(LOCAL_PATH)/includeLocal
LOCAL_LDLIBS := -llog
LOCAL_MODULE:= nativecalc
include $(BUILD_SHARED_LIBRARY)
android-config.mk
LOCAL_CFLAGS += -DOPENSSL_THREADS -D_REENTRANT -DDSO_DLFCN -DHAVE_DLFCN_H -DL_ENDIAN #-DTERMIO
# From DEPFLAG=
LOCAL_CFLAGS += -DOPENSSL_NO_CAMELLIA -DOPENSSL_NO_CAPIENG -DOPENSSL_NO_CAST -DOPENSSL_NO_CMS -DOPENSSL_NO_GMP -DOPENSSL_NO_IDEA -DOPENSSL_NO_JPAKE -DOPENSSL_NO_MD2 -DOPENSSL_NO_MDC2 -DOPENSSL_NO_RC5 -DOPENSSL_NO_SHA0 -DOPENSSL_NO_RFC3779 -DOPENSSL_NO_SEED -DOPENSSL_NO_STORE -DOPENSSL_NO_WHIRLPOOL
# Extra
LOCAL_CFLAGS += -DOPENSSL_NO_HW -DOPENSSL_NO_ENGINE -DZLIB
# Debug
# LOCAL_CFLAGS += -DCIPHER_DEBUG
Application.mk
APP_ABI := armeabi x86 mips
APP_PLATFORM := android-9
Any ideas how can I fix this in order for my native code to compile successfully?

NDK, LOCAL_EXPORT_C_INCLUDES not working as expected

Right now I am working on a native Android project and I want to use DevIL.
I don't want to put all the NDK code into one file, since DevIL needs multiple other libraries (libpng/libjpeg/...) and the Android.mk would end up being bloated.
I created a sub directory called Devil in my jni directory. I put all the code needed for DevIl (+ the libraries) in this directory. I also created an extra Android.mk file in this directory. In my "main" Android.mk file I added$(call import-module,DevIL) as well as: LOCAL_SHARED_LIBRARIES += libdevil. In the DevIL Android.mk I created an libdevil module and I used LOCAL_EXPORT_C_INCLUDES to link to the DevIL header files. When I put #include into my main.cpp file the ndk-build fails and complains "No such file or directory" in regards to the included header. If I don't put the #include into the code, the code compiles fine and all the shared libraries are created and put into the libs folder. What am I doing wrong?
My Main Android.mk
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
include cflags.mk
LOCAL_MODULE := arm
LOCAL_SRC_FILES := main.cpp
LOCAL_SHARED_LIBRARIES += libdevil
include $(BUILD_SHARED_LIBRARY)
$(call import-module,DevIL)
The Android.mk used for DevIl
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
include cflags.mk
JPEG_SRC_PATH := Libjpeg/
DEVIL_SRC_PATH := DevIL/
#many more
#libjpeg
include $(CLEAR_VARS)
LOCAL_MODULE := libjpeg
LOCAL_C_INCLUDES := ${JPEG_SRC_PATH}
FILE_LIST := $(wildcard $(LOCAL_PATH)/JPEG_SRC_PATH/*.c)
LOCAL_SRC_FILES := $(FILE_LIST:$(LOCAL_PATH)/%=%)
include $(BUILD_SHARED_LIBRARY)
#many other libraries; basically the same as libjpeg
#libdevil
include $(CLEAR_VARS)
LOCAL_MODULE := libdevil
LOCAL_EXPORT_C_INCLUDES := \
${DEVIL_SRC_PATH}include \
${DEVIL_SRC_PATH}src-IL/include \
#many more
FILE_LIST := $(wildcard $(LOCAL_PATH)/DEVIL_SRC_PATHsrc-IL/src/*.c)
LOCAL_SRC_FILES := $(FILE_LIST:$(LOCAL_PATH)/%=%)
LOCAL_STATIC_LIBRARIES := \
libjpeg \
#many more
LOCAL_LDLIBS += -lz
include $(BUILD_SHARED_LIBRARY)
The cflags.mk file
LOCAL_CFLAGS := -DANDROID_NDK
LOCAL_CFLAGS += -Werror
LOCAL_CFLAGS += -Wall
LOCAL_CFLAGS += -Wextra
LOCAL_CFLAGS += -Wno-strict-aliasing
LOCAL_CFLAGS += -Wno-unused-parameter
LOCAL_CFLAGS += -Wno-missing-field-initializers
LOCAL_CFLAGS += -Wno-multichar
LOCAL_CPPFLAGS := -Wno-type-limits
LOCAL_CPPFLAGS += -Wno-invalid-offsetof
LOCAL_CPPFLAGS += -std=c++11
LOCAL_CFLAGS += -std=c++11
LOCAL_CFLAGS += -fexceptions
LOCAL_CFLAGS += -Wno-error=deprecated-declarations
LOCAL_ARM_MODE := arm
Structure of the Directories
jni
|
+-- main.cpp
+-- Android.mk <- main Android
+-- Application.mk
+-- cflags.mk
|
+--DevIL
|
+-- Android.mk <- the Android.mk for DevIL
+-- cflags.mk
+--DevIL <-Directory containing DevIL source code
+--Libjpeg <-Directory containing code of specific DevIL dependency
+--...<-Directory containing code of specific DevIL dependency
Edit:
I noticed that I did not add my Application.mk, thus my Application.mk
Application.mk
APP_PLATFORM := android-19
APP_ABI := armeabi-v7a
APP_STL:=c++_static
APP_LDFLAGS := -Wl,--build-id
NDK_TOOLCHAIN_VERSION := 4.9
ROOT_DIR := $(patsubst %/,%,$(dir $(lastword $(MAKEFILE_LIST))))
NDK_MODULE_PATH := $(ROOT_DIR)

This does not answer the question, but if you are here from a search engine and happen to be having issues with LOCAL_EXPORT_C_INCLUDES on an AOSP module (not an NDK project!), Google's documentation at https://developer.android.com/ndk/guides/android_mk.html applies only to NDK projects.
For AOSP modules, the variable name is LOCAL_EXPORT_C_INCLUDE_DIRS, not LOCAL_EXPORT_C_INCLUDES.

NDK cannot locate symbol "_Znwj"

I've compiled a 3rd party library on Linux using a standalone toolchain, and I'm now trying to load that library in my app.
Problem is I'm getting java.lang.UnsatisfiedLinkError: dlopen failed: cannot locate symbol "_Znwj" referenced by "libmxnet_predict.so"
I've tried adding CFLAGS and LDFLAGS, both APP & LOCAL, but to no avail.
Before you ask, I'm developing with ADT because I have to.
This is my Application.mk:
APP_STL := gnustl_shared
APP_CFLAGS += -std=c++11
APP_CPPFLAGS := -frtti -fexceptions
APP_ABI := armeabi-v7a
APP_PLATFORM := android-19
My (simplified) Android.mk:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
OPENCV_LIB_TYPE:=SHARED
OPENCV_CAMERA_MODULES:=off
OPENCV_INSTALL_MODULES:=on
NDK_TOOLCHAIN_VERSION=4.9
include $(CLEAR_VARS)
include $(PREBUILT_SHARED_LIBRARIES)
include C:/OpenCV-2.4.8-android-sdk/sdk/native/jni/OpenCV.mk
LOCAL_MODULE := FreshubML
LOCAL_C_INCLUDES += $(LOCAL_PATH)
LOCAL_SRC_FILES := Mldevlib.cpp \
Tablet.cpp \
Interface.cpp \
LOCAL_LDLIBS += -llog -ldl -landroid -lm -ljnigraphics -lstdc++
C:\KitchenVision\Workspaces\MLDevWorkspace\MLDev\assets\share
include $(BUILD_SHARED_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := libmxnet_predict
LOCAL_SRC_FILES := lib/armeabi-v7a/libmxnet_predict.so
include $(PREBUILT_SHARED_LIBRARY)
Searching the standalone toolchain I saw that the symbol was referenced in libgnust_shared.so which I added to my project via APP_STL and in libstdc++.so but still, same error.
How do I get this to work?

Android-NDK: incompatible target while linking ZeroMQ static library into a shared library

I have successfully compiled multiple static libraries with the ndk toolchain and linked them into my own project. I have to use many cpp files and they need protocol buffers and a ZeroMQ, as a library, to compile successfully. Linking against protocol buffers works great, however, when I link against the ZeroMQ I get the following error:
C:/Users/x/ndk/toolchains/arm-linux-androideabi-4.9/prebuilt/windows- x86_64/bin/../lib/gcc/arm-linux-androideabi/4.9/../../../../arm-linux- androideabi/bin/ld.exe: error: ./zmq/lib/libzmq.a(libzmq
_la-zmq.o): incompatible target
collect2.exe: error: ld returned 1 exit status
make.exe: *** [C:/Users/x/Workspace/y/app/src/main//obj/local/armeabi- v7a/libZ.so] Error 1
I have replaced personal information with x, y, z for a clear reason.
I'm using Windows 8.1 with Android Studio 1.1 RC1 and NDK10d. I compiled the libraries on a Ubuntu and a Debian system (tried different ones). Both use the same arm toolchain.
To compile ZeroMQ I followed the steps from the official page. I tried zeromq3-x and zeromq4-x. I tried the mentioned ndk8 and the new ndk10d.
My Application.mk:
APP_STL := gnustl_static #tried: c++_static/shared stlport_static/shared
APP_PLATFORM := android-21
APP_USE_CPP0X := true #tried to omit
APP_CXXFLAGS := -std=gnu++11
APP_CPPFLAGS := -frtti -fexceptions --std=c++11
APP_ABI := armeabi-v7a #tried different like armeabi, all, x86 - obviously only arm should work
NDK_TOOLCHAIN_VERSION := 4.9
Android.mk without important files to compile because it will crash on the first need of zmq:
LOCAL_PATH := $(call my-dir)
include $(CLEAR_VARS)
LOCAL_MODULE := ../jni/protobuf
LOCAL_SRC_FILES := ../jni/protobuf/libprotobuf.a
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
LOCAL_EXPORT_C_INCLUDES := C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf-2.6.0\build\include
LOCAL_EXPORT_C_INCLUDES := C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf- 2.6.0\build\include\google
LOCAL_EXPORT_C_INCLUDES := C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf- 2.6.0\build\include\google\proto
LOCAL_C_INCLUDES := C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf- 2.6.0\build\include
LOCAL_C_INCLUDES := C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf-2.6.0\build\include\google
LOCAL_C_INCLUDES := C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf-2.6.0\build\include\google\protobuf
include $(PREBUILT_STATIC_LIBRARY)
LOCAL_MODULE := zmq
LOCAL_SRC_FILES := zmq/lib/libzmq.a
LOCAL_EXPORT_C_INCLUDES := $(LOCAL_PATH)/include
LOCAL_EXPORT_C_INCLUDES := C:\Users\x\Android\ZMQ\ARM-FINAL\include
LOCAL_EXPORT_C_INCLUDES := zmq/include
LOCAL_C_INCLUDES := C:\Users\x\Android\ZMQ\ARM-FINAL\include
LOCAL_C_INCLUDES := zmq/include
include $(PREBUILT_STATIC_LIBRARY)
include $(CLEAR_VARS)
LOCAL_MODULE := Z
LOCAL_CFLAGS := -I/zmq -std=c++11
LOCAL_CPPFLAGS := -I/zmq -std=c++11
LOCAL_CPP_FEATURES += exceptions
LOCAL_LDLIBS := -lGLESv1_CM -ldl -llog
LOCAL_CPP_EXTENSION := .cxx .cpp .cc .h
LOCAL_DISABLE_FORMAT_STRING_CHECKS := true
LOCAL_SRC_FILES := \
../jni/protogen/applications.pb.cc \ # this will work
common/bytearray.cpp \ # this will fail
LOCAL_ALLOW_UNDEFINED_SYMBOLS := true
LOCAL_C_INCLUDES += C:\Users\x\Android-MasterUI\app\src\main\jni
LOCAL_C_INCLUDES += ../jni/protogen
LOCAL_C_INCLUDES += common
LOCAL_C_INCLUDES += C:\Users\x\Android\ZMQ\ARM-FINAL\include
LOCAL_C_INCLUDES += C:\Users\x\Workspace\\app\src\main\jni\protobuf
LOCAL_C_INCLUDES += C:\Users\x\Workspace\Android- MasterUI\app\src\main\jni\protobuf\include
LOCAL_C_INCLUDES += C:\Users\x\Android- MasterUI\app\src\main\jni\protobuf\include\google
LOCAL_C_INCLUDES += C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf-2.6.0\build\include
LOCAL_C_INCLUDES += C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf- 2.6.0\build\include\google
LOCAL_C_INCLUDES += C:\Users\x\Android\Proto\.lib arm 5 2.6\protobuf-2.6.0\build\include\google\protobuf
LOCAL_STATIC_LIBRARIES := zmq protobuf
include $(BUILD_SHARED_LIBRARY)
The objdump from the static library looks like this
libzmq_la-address.o: file format elf64-x86-64
architecture: i386:x86-64, flags 0x00000011:
HAS_RELOC, HAS_SYMS
start address 0x0000000000000000
I will omit the further ones because they are all the same. There was a better way to dump all the pieces of information with more details about the architecture, but I can not find it anymore.
If you know a better way you may tell me and I will add more information.
Any idea is welcome and appreciated...