Re: Problem linking the Class++ example with Conan and CMake

[Akim Demaille]

> Le 30 juin 2019 à 18:45, Wouter Beek <address@hidden> a écrit :
> 
> Hi,

Hi Wouter,

> I'm trying to build the example calc++ program with Conan and CMake:
> https://github.com/wouterbeek/conan-cmake-bison-flex

That sounds interesting!

> The promise of Conan and CMake is that one could ultimately build a
> Flex/Bison program on multiple platforms, which is more difficult with
> traditional build systems.
> 
> Unfortunately, I'm currently stuck at the linking phase (see the
> output below).  Does anybody know what I'm doing wrong / how to
> proceed?

Well, your instruction to clone and compile are obsolete, the project,
I guess, has changed name.  And indeed, it does not work, but sooner
than in your case.

> -- Conan: Automatic detection of conan settings from cmake
> In file included from <stdin>:1:
> In file included from 
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string:500:
> In file included from 
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string_view:176:
> In file included from 
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/__string:56:
> In file included from 
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/algorithm:642:
> In file included from 
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/cstring:61:
> /Applications/Xcode.app/Contents/Developer/Toolchains/XcodeDefault.xctoolchain/usr/include/c++/v1/string.h:61:15:
>  fatal error: 'string.h' file not found
> #include_next <string.h>
>               ^~~~~~~~~~
> 1 error generated.
> -- Conan: Settings= 
> -s;build_type=Debug;-s;compiler=apple-clang;-s;compiler.version=10.0;-s;compiler.libcxx=libc++
> -- Conan executing: conan install /tmp/conan-cmake-bison-flex/conanfile.txt 
> -s build_type=Debug -s compiler=apple-clang -s compiler.version=10.0 -s 
> compiler.libcxx=libc++ -g=cmake --build=missing
> CMake Error at Debug/conan.cmake:399 (message):
>   Conan install failed='No such file or directory'
> Call Stack (most recent call first):
>   Debug/conan.cmake:485 (conan_cmake_install)
>   CMakeLists.txt:9 (conan_cmake_run)
> 
> 
> -- Configuring incomplete, errors occurred!
> See also "/tmp/conan-cmake-bison-flex/Debug/CMakeFiles/CMakeOutput.log".


> PS: The Calc++ example seems to be partially missing from Git master.
> Is this intentional?

Yes, it is extracted from the documentation.  You should start from a
tarball to get the full example.


> /home/wbeek/.conan/data/bison/3.3.2/bincrafters/stable/package/7e924ee4fb46c796a19516dcf956dd2bc0171a91/bin/bison
> --defines=/home/wbeek/tmp/calc++/Debug/Parser.hpp -o
> /home/wbeek/tmp/calc++/Debug/Parser.cpp
> /home/wbeek/tmp/calc++/Parser.yy
> cd /home/wbeek/tmp/calc++/Debug && /usr/bin/cmake -E cmake_depends
> "Unix Makefiles" /home/wbeek/tmp/calc++ /home/wbeek/tmp/calc++
> /home/wbeek/tmp/calc++/Debug /home/wbeek/tmp/calc++/Debug
> /home/wbeek/tmp/calc++/Debug/CMakeFiles/calc++.dir/DependInfo.cmake
> --color=
> Dependee "/home/wbeek/tmp/calc++/Debug/CMakeFiles/calc++.dir/DependInfo.cmake"
> is newer than depender
> "/home/wbeek/tmp/calc++/Debug/CMakeFiles/calc++.dir/depend.internal".
> Dependee 
> "/home/wbeek/tmp/calc++/Debug/CMakeFiles/CMakeDirectoryInformation.cmake"
> is newer than depender
> "/home/wbeek/tmp/calc++/Debug/CMakeFiles/calc++.dir/depend.internal".
> Scanning dependencies of target calc++
> gmake[2]: Leaving directory '/home/wbeek/tmp/calc++/Debug'
> /usr/bin/gmake -f CMakeFiles/calc++.dir/build.make CMakeFiles/calc++.dir/build
> gmake[2]: Entering directory '/home/wbeek/tmp/calc++/Debug'

Reading build logs from cmake is really painful.

> [ 50%] Building CXX object CMakeFiles/calc++.dir/Driver.cpp.o
> /usr/bin/c++   -I/home/wbeek/tmp/calc++/Debug -I/home/wbeek/tmp/calc++
> -g   -o CMakeFiles/calc++.dir/Driver.cpp.o -c
> /home/wbeek/tmp/calc++/Driver.cpp
> [ 66%] Building CXX object CMakeFiles/calc++.dir/Parser.cpp.o
> /usr/bin/c++   -I/home/wbeek/tmp/calc++/Debug -I/home/wbeek/tmp/calc++
> -g   -o CMakeFiles/calc++.dir/Parser.cpp.o -c
> /home/wbeek/tmp/calc++/Debug/Parser.cpp
> [ 83%] Building CXX object CMakeFiles/calc++.dir/Lexer.cpp.o
> /usr/bin/c++   -I/home/wbeek/tmp/calc++/Debug -I/home/wbeek/tmp/calc++
> -g   -o CMakeFiles/calc++.dir/Lexer.cpp.o -c
> /home/wbeek/tmp/calc++/Debug/Lexer.cpp
> [100%] Linking CXX executable bin/calc++
> /usr/bin/cmake -E cmake_link_script CMakeFiles/calc++.dir/link.txt --verbose=1
> /usr/bin/c++    -g   CMakeFiles/calc++.dir/Driver.cpp.o
> CMakeFiles/calc++.dir/Parser.cpp.o CMakeFiles/calc++.dir/Lexer.cpp.o
> -o bin/calc++ 
> /home/wbeek/.conan/data/flex/2.6.4/bincrafters/stable/package/7e924ee4fb46c796a19516dcf956dd2bc0171a91/lib/libfl.a
> /usr/bin/ld: 
> /home/wbeek/.conan/data/flex/2.6.4/bincrafters/stable/package/7e924ee4fb46c796a19516dcf956dd2bc0171a91/lib/libfl.a(libmain.o):
> in function `main':
> /home/wbeek/.conan/data/flex/2.6.4/bincrafters/stable/build/7e924ee4fb46c796a19516dcf956dd2bc0171a91/source_subfolder/src/libmain.c:33:
> undefined reference to `yylex'

Have you checked the content of the scanner file?  Have you used `nm` to look 
for the names of the symbols in the object files and see where yylex is defined?