6.0.1 Version of exception_skeleton use case execution compilation error.

[simon28li]

As in the title, the following is the error log. It looks like you need to use c++17. I added-DCMAKE_CXX_FLAGS="-std=c++17" when compiling, but it was not solved. Can you provide some help?

1800: In file included from /home/stage/root/spack-stage-cgal-6.0.1-773syjfc4tn2c5xicnvnjtsk7hydvihn/spack-src/examples/Straight_skeleton_2/extrude_skeleton.cpp:9:0:
1800: /home/stage/root/spack-stage-cgal-6.0.1-773syjfc4tn2c5xicnvnjtsk7hydvihn/spack-src/examples/Straight_skeleton_2/include/CGAL/input_helpers.h: In function 'bool read_dat_polygon(const char*, PolygonWithHoles&)':
1800: /home/stage/root/spack-stage-cgal-6.0.1-773syjfc4tn2c5xicnvnjtsk7hydvihn/spack-src/examples/Straight_skeleton_2/include/CGAL/input_helpers.h:39:11: error: 'std::filesystem' has not been declared
1800:    if(std::filesystem::path(filename).extension().string() == ".poly")
1800:            ^~~~~~~~~~
1800: /home/stage/root/spack-stage-cgal-6.0.1-773syjfc4tn2c5xicnvnjtsk7hydvihn/spack-src/examples/Straight_skeleton_2/include/CGAL/input_helpers.h: In function 'bool read_input_polygon(const char*, PolygonWithHoles&)':
1800: /home/stage/root/spack-stage-cgal-6.0.1-773syjfc4tn2c5xicnvnjtsk7hydvihn/spack-src/examples/Straight_skeleton_2/include/CGAL/input_helpers.h:112:26: error: 'std::filesystem' has not been declared
1800:    std::string ext = std::filesystem::path(filename).extension().string();
1800:                           ^~~~~~~~~~
1800: gmake[3]: *** [examples/Straight_skeleton_2/CMakeFiles/extrude_skeleton.dir/build.make:82: examples/Straight_skeleton_2/CMakeFiles/extrude_skeleton.dir/extrude_skeleton.cpp.o] Error 1
1800: gmake[2]: *** [CMakeFiles/Makefile2:27200: examples/Straight_skeleton_2/CMakeFiles/extrude_skeleton.dir/all] Error 2
1800: gmake[1]: *** [CMakeFiles/Makefile2:27207: examples/Straight_skeleton_2/CMakeFiles/extrude_skeleton.dir/rule] Error 2
1800: gmake: *** [Makefile:10646: extrude_skeleton] Error 2
3/5 Test #1800: compilation of  extrude_skeleton ..................***Failed   23.31 sec
test 1801
    Start 1801: execution   of  extrude_skeleton
Failed test dependencies: compilation of  extrude_skeleton
4/5 Test #1801: execution   of  extrude_skeleton ..................***Not Run   0.00 sec
test 1779
    Start 1779: cleanup of Straight_skeleton_2_Examples

1779: Test command: /home/spack/opt/spack/linux-sles15-aarch64/gcc-7.4.0/cmake-3.19.5-alpemy5iohhkss3uk4trysqo7457eiap/bin/cmake "-E" "remove_directory" "/home/stage/root/spack-stage-cgal-6.0.1-773syjfc4tn2c5xicnvnjtsk7hydvihn/spack-src/build/examples/Straight_skeleton_2/__exec_test_dir"
1779: Test timeout computed to be: 10000000
5/5 Test #1779: cleanup of Straight_skeleton_2_Examples ...........   Passed    0.00 sec

The following tests passed:
        check build system
        copy source_dir of Straight_skeleton_2_Examples
        cleanup of Straight_skeleton_2_Examples

60% tests passed, 2 tests failed out of 5

Label Time Summary:
CGAL_build_system               =   0.27 sec*proc (1 test)
Installation                    =   0.27 sec*proc (1 test)
Straight_skeleton_2_Examples    =  23.32 sec*proc (4 tests)

Total Test time (real) =  23.75 sec

The following tests FAILED:
        1800 - compilation of  extrude_skeleton (Failed)
        1801 - execution   of  extrude_skeleton (Not Run)

[lrineau]

For CGAL-6.0.1 or later, your compiler must be set up with C++17 or later. Is that the case? Can we see the compilation command lines?

[lrineau]

Actually, if your compiler is gcc 7.4.0 (as the path /home/spack/opt/spack/linux-sles15-aarch64/gcc-7.4.0/ seems to indicate), it is unfortunately too old for C++17 <filsystem>. Gcc version 8 or later is required. See:

• https://en.cppreference.com/w/cpp/compiler_support/17#C.2B.2B17_library_features and
• https://gcc.gnu.org/gcc-8/changes.html#libstdcxx.