[FTBS] opensuse 15.4 linking of tests ok in v0.2.6 but fails both in v0.3 and latest r.46f826c

[Corin-EU]

[FTBS] opensuse 15.4 linking of tests ok in v0.2.6 but fails both in v0.3 and latest r.46f826c

[thezbyg]

Hi,
most likely this is due to switch to C++ Lua library variant in 892a81e.
Linker errors are caused by Lua function declarations using C++ linkage when Lua library exports C style functions.
Debian based distributions have this patch: https://sources.debian.org/patches/lua5.4/5.4.2-2/0003-extern_C.patch/
Without this patch, all Lua header inclusions must be wrapped in extern "C" { } block when used from C++ code. I will restore these blocks.

GCC 8.2 is too old and is missing some C++17 features. GCC 10 should work once Lua includes are fixed.

[thezbyg]

Should be fixed in a8bc29c

[Corin-EU]

Thank you for looking at this problem.

opensuse 15.4
g++-10 (SUSE Linux) 10.4.0

latest gpick r.a8bc29c

I anticipated reporting back that all was now working, but I am still getting the same errors

              [ 31%] Linking CXX executable tests
              /usr/lib64/gcc/x86_64-suse-linux/10/../../../../x86_64-suse-linux/bin/ld: CMakeFiles/tests.dir/source/Converter.cpp.o: in function `Converter::serialize[abi:cxx11](ColorObject const&, ConverterSerializePosition const&)':
               Converter.cpp:(.text+0x398): undefined reference to `lua_gettop'
              /usr/lib64/gcc/x86_64-suse-linux/10/../../../../x86_64-suse-linux/bin/ld: Converter.cpp:(.text+0x3ed): undefined reference to `lua_createtable'

etc

So in the "build" sub-directory, I did a make VERBOSE=1

          /usr/local/stow/Development/cmake-3.19.6/bin/cmake -E cmake_link_script CMakeFiles/tests.dir/link.txt --verbose=1
          /usr/bin/g++-10 CMakeFiles/tests.dir/CMakeFiles/Version.cpp.o CMakeFiles/tests.dir/source/ColorList.cpp.o CMakeFiles/tests.dir/source/ColorObject.cpp.o CMakeFiles/tests.dir/source/Converter.cpp.o CMakeFiles/tests.dir/source/Converters.cpp.o CMakeFiles/tests.dir/source/ErrorCode.cpp.o CMakeFiles/tests.dir/source/EventBus.cpp.o CMakeFiles/tests.dir/source/FileFormat.cpp.o CMakeFiles/tests.dir/source/InternalConverters.cpp.o CMakeFiles/tests.dir/source/test/BinaryTreeQuantization.cpp.o CMakeFiles/tests.dir/source/test/Color.cpp.o CMakeFiles/tests.dir/source/test/Common.cpp.o CMakeFiles/tests.dir/source/test/Dynv.cpp.o CMakeFiles/tests.dir/source/test/DynvBinary.cpp.o CMakeFiles/tests.dir/source/test/EventBus.cpp.o CMakeFiles/tests.dir/source/test/FileFormat.cpp.o CMakeFiles/tests.dir/source/test/First.cpp.o CMakeFiles/tests.dir/source/test/Format.cpp.o CMakeFiles/tests.dir/source/test/InternalConverters.cpp.o CMakeFiles/tests.dir/source/test/Main.cpp.o CMakeFiles/tests.dir/source/test/Matrix.cpp.o CMakeFiles/tests.dir/source/test/OctreeColorQuantization.cpp.o CMakeFiles/tests.dir/source/test/Ref.cpp.o CMakeFiles/tests.dir/source/test/Result.cpp.o CMakeFiles/tests.dir/source/test/Scoped.cpp.o CMakeFiles/tests.dir/source/test/Script.cpp.o CMakeFiles/tests.dir/source/test/Span.cpp.o CMakeFiles/tests.dir/source/test/TextFileParser.cpp.o CMakeFiles/tests.dir/source/test/Vector.cpp.o CMakeFiles/gpick-color.dir/source/Color.cpp.o CMakeFiles/gpick-math.dir/source/math/BinaryTreeQuantization.cpp.o CMakeFiles/gpick-math.dir/source/math/Empty.cpp.o CMakeFiles/gpick-math.dir/source/math/OctreeColorQuantization.cpp.o CMakeFiles/gpick-dynv.dir/source/dynv/Binary.cpp.o CMakeFiles/gpick-dynv.dir/source/dynv/Map.cpp.o CMakeFiles/gpick-dynv.dir/source/dynv/Types.cpp.o CMakeFiles/gpick-dynv.dir/source/dynv/Variable.cpp.o CMakeFiles/gpick-dynv.dir/source/dynv/Xml.cpp.o CMakeFiles/gpick-lua.dir/source/lua/Color.cpp.o CMakeFiles/gpick-lua.dir/source/lua/ColorObject.cpp.o CMakeFiles/gpick-lua.dir/source/lua/Ref.cpp.o CMakeFiles/gpick-lua.dir/source/lua/Script.cpp.o CMakeFiles/gpick-parser.dir/source/parser/TextFile.cpp.o CMakeFiles/gpick-parser.dir/CMakeFiles/TextFileParser.cpp.o CMakeFiles/gpick-common.dir/source/common/Convert.cpp.o CMakeFiles/gpick-common.dir/source/common/Format.cpp.o CMakeFiles/gpick-common.dir/source/common/Ref.cpp.o CMakeFiles/gpick-common.dir/source/common/StringOrView.cpp.o -o tests  /usr/lib64/libboost_unit_test_framework.so -lexpat -lm -pthread

which obviously gave the same error.

I then repeated the command and put a "-llua" at the very end, ie just after "-lm -pthread" and then there was no error and linking was successful.

So it would appear the error is somewhere in the CMakefile process and that the "lua" library dependency is not being added to the needed shared library link list for some reason (unlike back in v0.2.6).