ZLib Linking error

[sromer]

Hi,

I am currently trying to build the FIFEngine tutorial, but I am getting stuck at the following error:

sromer@ubuntu:~/Development/cpp-tutorials/src/_build$ cmake ..
-- The C compiler identification is GNU 5.4.0
-- The CXX compiler identification is GNU 5.4.0
-- Check for working C compiler: /usr/bin/cc
-- Check for working C compiler: /usr/bin/cc -- works
-- Detecting C compiler ABI info
-- Detecting C compiler ABI info - done
-- Detecting C compile features
-- Detecting C compile features - done
-- Check for working CXX compiler: /usr/bin/c++
-- Check for working CXX compiler: /usr/bin/c++ -- works
-- Detecting CXX compiler ABI info
-- Detecting CXX compiler ABI info - done
-- Detecting CXX compile features
-- Detecting CXX compile features - done
-- Set CMAKE_BUILD_TYPE to default 'Release'.

== Building fife-cpp-tutorials using build type 'Release'.
--     Source directory is '/home/sromer/Development/cpp-tutorials/src'.
--     Build  directory is '/home/sromer/Development/cpp-tutorials/src/_build'.
--     Installation path is '/usr/local' (set -DCMAKE_INSTALL_PREFIX=<path> to change).
--     CXX Compiler Flags: ''.
--     Dependencies folder: '/home/sromer/Development/cpp-tutorials/src/../dependencies'.

-- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so;/usr/lib/x86_64-linux-gnu/libXext.so
-- Looking for XOpenDisplay in /usr/lib/x86_64-linux-gnu/libX11.so;/usr/lib/x86_64-linux-gnu/libXext.so - found
-- Looking for gethostbyname
-- Looking for gethostbyname - found
-- Looking for connect
-- Looking for connect - found
-- Looking for remove
-- Looking for remove - found
-- Looking for shmat
-- Looking for shmat - found
-- Looking for IceConnectionNumber in ICE
-- Looking for IceConnectionNumber in ICE - found
-- Found X11: /usr/lib/x86_64-linux-gnu/libX11.so
-- Found FIFE: /usr/local/lib/libfife.a (found version "0.4.0") 
-- Found the following FifeChan libraries:
--   fifechan_opengl
--   fifechan_sdl
-- Found FIFECHAN: /usr/local/lib/libfifechan.so   
-- Boost version: 1.58.0
-- Found the following Boost libraries:
--   system
--   filesystem
--   regex
-- Found VORBIS: /usr/lib/x86_64-linux-gnu/libvorbisfile.so  
-- Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.8") 
-- Found PNG: /usr/lib/x86_64-linux-gnu/libpng.so (found version "1.2.54") 
-- Found OGG: /usr/lib/x86_64-linux-gnu/libogg.so  
<FindSDL2.cmake>
-- Looking for pthread.h
-- Looking for pthread.h - found
-- Looking for pthread_create
-- Looking for pthread_create - not found
-- Looking for pthread_create in pthreads
-- Looking for pthread_create in pthreads - not found
-- Looking for pthread_create in pthread
-- Looking for pthread_create in pthread - found
-- Found Threads: TRUE  
</FindSDL2.cmake>
-- Found SDL2: /usr/lib/x86_64-linux-gnu/libSDL2main.a;/usr/lib/x86_64-linux-gnu/libSDL2.so;-lpthread  
-- Found SDL2_image: /usr/lib/x86_64-linux-gnu/libSDL2_image.so (found version "2.0.1") 
-- Found SDL2_ttf: /usr/lib/x86_64-linux-gnu/libSDL2_ttf.so (found version "2.0.14") 
-- Found OpenAL: /usr/lib/x86_64-linux-gnu/libopenal.so  
-- Found OpenGL: /usr/lib/x86_64-linux-gnu/libGL.so  
-- Found TinyXML: /usr/lib/x86_64-linux-gnu/libtinyxml.so  
-- Configuring done
-- Generating done
-- Build files have been written to: /home/sromer/Development/cpp-tutorials/src/_build
sromer@ubuntu:~/Development/cpp-tutorials/src/_build$ make
Scanning dependencies of target Tutorial1
[ 14%] Building CXX object tutorial_1/CMakeFiles/Tutorial1.dir/MouseListener.cpp.o
[ 28%] Building CXX object tutorial_1/CMakeFiles/Tutorial1.dir/ScreenScroller.cpp.o
[ 42%] Building CXX object tutorial_1/CMakeFiles/Tutorial1.dir/Game.cpp.o
[ 57%] Building CXX object tutorial_1/CMakeFiles/Tutorial1.dir/main.cpp.o
[ 71%] Building CXX object tutorial_1/CMakeFiles/Tutorial1.dir/KeyListener.cpp.o
[ 85%] Building CXX object tutorial_1/CMakeFiles/Tutorial1.dir/ViewController.cpp.o
[100%] Linking CXX executable Tutorial1
/usr/bin/ld: /usr/local/lib/libfife.a(zipsource.cpp.o): undefined reference to symbol 'inflateInit2_'
/usr/lib/gcc/x86_64-linux-gnu/5/../../../x86_64-linux-gnu/libz.so: error adding symbols: DSO missing from command line
collect2: error: ld returned 1 exit status
tutorial_1/CMakeFiles/Tutorial1.dir/build.make:268: recipe for target 'tutorial_1/Tutorial1' failed
make[2]: *** [tutorial_1/Tutorial1] Error 1
CMakeFiles/Makefile2:85: recipe for target 'tutorial_1/CMakeFiles/Tutorial1.dir/all' failed
make[1]: *** [tutorial_1/CMakeFiles/Tutorial1.dir/all] Error 2
Makefile:127: recipe for target 'all' failed
make: *** [all] Error 2

I figured libz.so might be missing from my system, but as you can see, CMake is able to find the libz library correctly: Found ZLIB: /usr/lib/x86_64-linux-gnu/libz.so (found version "1.2.8"). I have checked if the library is indeed installed and can be found/accessed at the folder in which CMake locates libz and that is the case.

I am running Ubuntu 16.04 LTS (x64).

Hopefully someone can help me out!

[LinuxDonald]

Give it an libz devel package maybe?

[sromer]

Wow @LinuxDonald you are fast!

The following libs are installed:

ii  zlib1g:amd64      1:1.2.8.dfsg-2ubuntu4  amd64   compression library - runtime
ii  zlib1g:i386       1:1.2.8.dfsg-2ubuntu4  i386    compression library - runtime
ii  zlib1g-dbg        1:1.2.8.dfsg-2ubuntu4  amd64   compression library - development
ii  zlib1g-dev:amd64  1:1.2.8.dfsg-2ubuntu4  amd64   compression library - development
ii  zlib1g-dev:i386   1:1.2.8.dfsg-2ubuntu4  i386    compression library - development

[LinuxDonald]

i will take an look later on it. I have tested it last time on ArchLinux and dont had any problems. But i have Ubuntu installed too i will test it and see what happens.

[sromer]

Just tested it on a clean Kubuntu install, because @milandamen has no problems with building on Kubuntu, but I am getting the same (undefined reference to symbol 'inflateInit2_') error as well. Don't have an ArchLinux install at the moment...

[LinuxDonald]

Have you installed all fife deps? https://github.com/fifengine/fifengine/wiki/Compiling-fife

[sromer]

Yes, all deps have been installed properly.

[jakoch]

We have find_package, include and finally target_link_directory for zlib on tutorial_1.
zlib is also on position 1 in the linking order, so that it's symbols "should be available" for following objects. Travis is also green for Linux.

Do you have any errors messages during building libfife?

[sromer]

Just cloned the fifengine repo and build from source. Have not seen any errors during the build process, also the installed ZLib library (1.2.8) is found.

cmake -> http://pastebin.com/McLVqHN4
make -> http://pastebin.com/nMsscz6r
make install -> http://pastebin.com/AZMttVBM

[jakoch]

Thank you for posting the logs.
According to the logs everything is fine: no compilation errors, nor errors regarding zlib.
All looking good.

What could help is to go into cmake verbose mode to see the linker commands.
Running make VERBOSE=1 should output more information.
If i would do the linking manually, i would use -lz.
But let's see what cmake does. It could be a library prefix or a path issue.

Another thing, which could help is, to output the vars from the library detection done by find_package(zlib). We need to check, if we get the correct values for ${ZLIB_INCLUDE_DIR} and especially ${ZLIB_LIBRARIES}.

Just add the following lines after find_package did it's job and the vars have been set.
Here:

cpp-tutorials/src/tutorial_1/CMakeLists.txt

Line 42 in 643bf4f

message("==> ZLIB_INCLUDE_DIR ${ZLIB_INCLUDE_DIR}")
message("==> ZLIB_LIBRARIES ${ZLIB_LIBRARIES}")

[sromer]

I have ran make with VERBOSE=1
Output: http://pastebin.com/yvwy0Naf

Also when adding the message statements to the cmake file I get the following output
==> ZLIB_INCLUDE_DIR /usr/include ==> ZLIB_LIBRARIES /usr/lib/x86_64-linux-gnu/libz.so

Which seem like the legit folders...

[jakoch]

Thank you. The message output is ok. libz.so is what we want to link.

The verbose output is for fifengine itself - and i noticed one issue, regarding Fifechan:

• -I/home/stephanromer/Development/fifengine/FIFECHAN_INCLUDE_DIR-NOTFOUND/fifechan

Seems the includes for fifechan are missing or not detected properly.
Referencing: fifengine/fifengine#938

The later maybe, because the old logs show that the lib is found Found FIFECHAN: /usr/local/lib/libfifechan.so.
I wonder, why this issue doesn't bubble up as an error in non-verbose mode.

---

Update: i've enabled verbose mode on Travis for Linux builds.

I could reproduce the Fifechan include issue

• https://travis-ci.org/fifengine/cpp-tutorials/jobs/171594264#L2437

But not the original zlib linking issue (the linker line contains -lz).

• https://travis-ci.org/fifengine/cpp-tutorials/jobs/171594264#L2450

[milandamen]

I recreated the exact problem in a VM running Ubuntu 64bit and I found a solution:

Instead of running cmake .. -Dbuild-library:BOOL=ON -DBUILD_SHARED_LIBS:BOOL=OFF on fifengine, you should run cmake .. -Dbuild-library:BOOL=ON -DBUILD_SHARED_LIBS:BOOL=ON.

That's it. The tutorial builds correctly now. It doesn't fix the original issue but it can be used as a workaround for the time being.