Mac OSX 10.10 - Include a QT Static Library *.a into a Eclipse CDT JNI Shared Library *jnilib (Download of the projekts available)

moozoom

Dear QT Community,

I am a QT beginner.
I will create a static library *.a with QT creator and make it reuseable for a other projekt.
This QT projekt ist downloadable as *.ZIP:

Download: http://moozoom.de/share/QT_vs_Java_JNI_over_CDT.zip

The *.pro file have following build information:

#-------------------------------------------------
#
# Project created by QtCreator 2015-06-13T16:02:21
#
#-------------------------------------------------

QT -= gui

TARGET = QTStaticLibrary
TEMPLATE = lib
CONFIG += staticlib

@CONFIG += MAC_CONFIG
MAC_CONFIG {
QMAKE_CXXFLAGS = -std=c++11 -stdlib=libstdc++ -mmacosx-version-min=10.10
QMAKE_LFLAGS = -std=c++11 -stdlib=libstdc++ -mmacosx-version-min=10.10
}

QMAKE_CFLAGS_RELEASE = -Os -momit-leaf-frame-pointer

SOURCES += qtstaticlibrary.cpp

HEADERS += qtstaticlibrary.h
unix {
target.path = /usr/lib
INSTALLS += target
}

I develop on Mac OS X 10.10 and create the static library (.a) with a clang (LLVM) compiler.
My main application based on JAVA because I need a special runtime environment - based on java.
I used Eclipse LUNA CDT for developing this application based on java jni for including a C++ shared library (.jnilib) (cpp compiler) over a CDT Eclipse plugin. A clang compiler is not available for the eclipse mac osx version.

Tutorial JNI:
https://www3.ntu.edu.sg/home/ehchua/programming/java/JavaNativeInterface.html

Include c++ libraries by eclipse cdt:
http://stackoverflow.com/questions/8332460/how-do-i-include-a-statically-linked-library-in-my-eclipse-c-project

The makefile for my helloJNI project:

# Define a variable for classpath
CLASS_PATH = ../bin

# Define a virtual path for .class in the bin directory
vpath %.class $(CLASS_PATH)

# Modify the "makefile" as follows to generate the shared library "libHello.jnilib" for Mac.

all : libHello.jnilib

# $@ matches the target, $< matches the first dependancy
# The -lstdc++ flag tells the linker to include the C++ Standard Library
libHello.jnilib : HelloQT2JNI.o
g++ -lstdc++ -v -Wl -shared -o $@ $< libQTStaticLibrary.a

# $@ matches the target, $< matches the first dependancy
# -c flag to tell the compiler to skip the link stage: "ld: symbol(s) not found for architecture x86_64"
HelloQT2JNI.o : HelloQT2JNI.cpp HelloQT2JNI.h
gcc -I"/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/include" -I"/Library/Java/JavaVirtualMachines/jdk1.8.0_45.jdk/Contents/Home/include/darwin" -c $< -o $@

# $* matches the target filename without the extension
HelloQT2JNI.h : HelloQT2JNI.class
javah -classpath $(CLASS_PATH) $*

clean :
rm HelloQT2JNI.h HelloQT2JNI.o libHello.jnilib

Call the func hello() in my qt static library in my jni-class:

#include <jni.h>
#include <iostream>
#include "HelloQT2JNI.h"

#include "qtstaticlibrary.h"

using namespace std;

JNIEXPORT void JNICALL Java_HelloQT2JNI_sayHello__(JNIEnv *, jobject)
{
cout << "Hello World!" << endl;

QTStaticLibrary hello = QTStaticLibrary();
hello.hello();

return;
}

How I can include my static library *.a (clang compiled) into my shared library *.jnilib (cpp compiler) over my makefile? I will use my qt static library in my java project over java jni.

I received following CDT Build Console error message:

make all
javah -classpath ../bin HelloQT2JNI
g++ -lstdc++ -v -Wl -shared -o libHello.jnilib HelloQT2JNI.o libQTStaticLibrary.a
Apple LLVM version 6.1.0 (clang-602.0.53) (based on LLVM 3.6.0svn)
Target: x86_64-apple-darwin14.3.0
Thread model: posix
"/Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/ld" -demangle -dynamic -dylib -arch x86_64 -macosx_version_min 10.10.0 -syslibroot /Applications/Xcode.app/Contents/Developer/Platforms/MacOSX.platform/Developer/SDKs/MacOSX10.10.sdk -o libHello.jnilib -lc++ HelloQT2JNI.o libQTStaticLibrary.a -lc++ -lSystem /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/bin/../lib/clang/6.1.0/lib/darwin/libclang_rt.osx.a
Undefined symbols for architecture x86_64:
"std::basic_ios<char, std::char_traits<char> >::widen(char) const", referenced from:
QTStaticLibrary::hello() const in libQTStaticLibrary.a(qtstaticlibrary.o)
"std::ostream::put(char)", referenced from:
QTStaticLibrary::hello() const in libQTStaticLibrary.a(qtstaticlibrary.o)
"std::ostream::flush()", referenced from:
QTStaticLibrary::hello() const in libQTStaticLibrary.a(qtstaticlibrary.o)
"std::ios_base::Init::Init()", referenced from:
__GLOBAL__sub_I_qtstaticlibrary.cpp in libQTStaticLibrary.a(qtstaticlibrary.o)
"std::ios_base::Init::~Init()", referenced from:
__GLOBAL__sub_I_qtstaticlibrary.cpp in libQTStaticLibrary.a(qtstaticlibrary.o)
"std::basic_ostream<char, std::char_traits<char> >& std::__ostream_insert<char, std::char_traits<char> >(std::basic_ostream<char, std::char_traits<char> >&, char const*, long)", referenced from:
QTStaticLibrary::hello() const in libQTStaticLibrary.a(qtstaticlibrary.o)
"std::cout", referenced from:
QTStaticLibrary::hello() const in libQTStaticLibrary.a(qtstaticlibrary.o)
ld: symbol(s) not found for architecture x86_64
clang: error: linker command failed with exit code 1 (use -v to see invocation)
make: *** [libHello.jnilib] Error 1

The qt project and the clipse LUNA cdt project is downloadable as *.ZIP:

Download: http://moozoom.de/share/QT_vs_Java_JNI_over_CDT.zip

Actually the jni project is runable. The qt files can u find in the dir „jni/<qtstaticlibrary.h, libQTStaticLibrary.a>“.

Please help my. I am very frustrated. QT is a very interesting framework for using in java over jni.

Thank u in advanced :-)

Sir.Costy

@moozoom
I run in the same paradigm when I try to create a static linked library with Qt targeting Android and latter to use it with JINI on Android Studio.
Reading you post I see you have almost the same problem like me with one difference.
To me are working as far I use only std library
My problem appears when I use QString for example in the library.
Looks the static build does not statically includes the Qt framework dependencies.
Finally did you find a solution? Me I run with this issue past over one month.
Thanks