I am attempting to cross-compile our C++ code base (using CMake) for the Android platform using the r5b NDK on Ubuntu 10.10. The compile phase succeeds, however during the final link phase for the .so there are many unresolved references to symbols that are in the libsupc++.a file (which I specify to link in). I have also tried -lsupc++ with no difference.
I tried to follow the command-line as closely as possible as generated by the official ndk-build system when building the test-gnustl-1 NDK test app.
Running the arm-linux-androideabi-nm tool on the arm-linux-androideabi/lib/libsupc++.a file shows the symbols as defined (T) referenced in the error output.
An example of a symbol defined in libsupc++ it cannot find is: __gxx_personality_v0
Here is my sample link line and a resulting sample of errors.
/home/user/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/bin/arm-linux-androideabi-g++ -fPIC -Wall -Wextra -Wno-unused -Wno-multichar -fno-rtti -MMD -MP -MF -ffunction-sections -fexceptions -funwind-tables -Wno-psabi -march=armv5te -mtune=xscale -msoft-float -mthumb -fomit-frame-pointer -fno-strict-aliasing -finline-limit=64 -Wa,--noexecstack -DANDROID -D__ARM_ARCH_5__ -D__ARM_ARCH_5T__ -D__ARM_ARCH_5E__ -D__ARM_ARCH_5TE__ -O0 -DDEBUG -D_DEBUG -g --sysroot=/home/user/android-ndk-r5b/platforms/android-9/arch-arm -Wl,--gc-sections -Wl,-z,nocopyreloc -Wl,--no-undefined,-z,noexecstack -L/home/user/android-ndk-r5b/platforms/android-9/arch-arm/usr/lib -L/home/user/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/arm-linux-androideabi/lib -Wl,-rpath-link=/home/user/android-ndk-r5b/platforms/android-9/arch-arm/usr/lib /home/user/android-ndk-r5b/sources/cxx-stl/gnu-libstdc++/libs/armeabi/libstdc++.a -lc -lsupc++ -shared -o ../../lib/Debug/libFoo.so CMakeFiles/Foo.dir/Foo.c.o CMakeFiles/Foo.dir/Bar.cpp.o CMakeFiles/Foo.dir/Baz.cpp.o
`CMakeFiles/Foo.dir/Foo.cpp.o: In function 'myFunc':
/home/user/myroj/src/native/modules/libFoo/Foo.cpp:292: undefined reference to '__cxa_end_cleanup'
CMakeFiles/Foo.dir/Foo.cpp.o:(.ARM.extab.text.myFunc+0x0): undefined reference to '__gxx_personality_v0'
...
/home/user/android-ndk-r5b/toolchains/android/sources/cxx-stl/gnu-libstdc++/include/bits/vector.tcc:350: undefined reference to '__cxa_begin_catch'
/home/user/android-ndk-r5b/toolchains/android/sources/cxx-stl/gnu-libstdc++/include/bits/vector.tcc:357: undefined reference to '__cxa_rethrow'
/home/user/android-ndk-r5b/toolchains/android/sources/cxx-stl/gnu-libstdc++/include/bits/stl_vector.h:1153: undefined reference to 'std::__throw_length_error(char const*)'
/home/user/android-ndk-r5b/toolchains/android/sources/cxx-stl/gnu-libstdc++/include/bits/stl_tree.h:199: undefined reference to 'std::_Rb_tree_decrement(std::_Rb_tree_node_base*)'
...
I tried to creating a simple hello-world app that makes use of exceptions and links in a simple .a file. I got the same errors until I linked in the libsupc++.a library directly instead of using ‘-lsupc++’. However, this same technique did not work on the larger project link step. The NDK docs also suggest ‘-lsupc++’ is should be used when using external build tools.
I am out of ideas on how to resolve this linking issue. I have tried reordering the link line as many ways as I could think of. I know linking in general can be a fickle process.
Any help is greatly appreciated.
It turns out I needed to add
-L/home/user/android-ndk-r5b/sources/cxx-stl/gnu-libstdc++/libs/armeabi"to the path and explicitly link “/home/user/android-ndk-r5b/toolchains/arm-linux-androideabi-4.4.3/prebuilt/linux-x86/arm-linux-androideabi/lib/thumb/libsupc++.a” with all include libraries wrapped in a “--start-group --end-group” clause.Hopefully this helps someone else too.