cmake flag to skip a specific example?

[David Montiel]

I am trying to install deal.II in a cluster and somehow the compiler is not recognizing std::filesystem which is used in step-83. However step-83 isn't marked as having unmet dependencies. 

As a results the "make" I use for building deal.II fails when building step-83

I can probably modify the CMakeLists.txt file within step-83 but I was hoping to instead introduce a flag during CMake to force skip step-83 instead. 

Can I do that without disabling the rest of the examples, as in DEAL_II_COMPONENT_EXAMPLES=OFF?

Any other better options?

Thank you!

David

[Wolfgang Bangerth]

If you don't actually care about step-83, then just comment out the offending
lines in step-83 before compiling deal.II. The program won't work correctly,
of course, but at least you can proceed with the installation.

Out of curiosity: What is the compiler you are using, and how does the error
message you get look like?

Best
W.

--
------------------------------------------------------------------------
Wolfgang Bangerth email: bang...@colostate.edu
www: http://www.math.colostate.edu/~bangerth/

[Matthias Maier]

On Thu, Feb 6, 2025, at 09:40 CST, David Montiel <dmon...@umich.edu> wrote:

> Can I do that without disabling the rest of the examples, as in
> DEAL_II_COMPONENT_EXAMPLES=OFF?

You can simply set -DDEAL_II_COMPILE_EXAMPLES=OFF and it will install
the examples in source form only.

We have removed compilation of example steps from the build system
entirely in the current development version.

Best,
Matthias

[David Montiel]

Thank you both for your suggestions!

Wolfgang, I am using ICC 2021.5.0 which as far as I know fully supports the C++17 standard, including the std::filesystem library. So who knows what is going on. 

I tried including the flag -DDEAL_II_CXX_FLAGS="-lstdc++fs" but that still didn't work. 

The error message I am getting is 

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::__cxx11::path::_M_split_cmpts()'

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::__cxx11::directory_iterator::directory_iterator(std::filesystem::__cxx11::path const&, std::filesystem::directory_options, std::error_code*)'

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::__cxx11::directory_iterator::operator*() const'

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::__cxx11::directory_iterator::operator++()'

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::__cxx11::path::_M_split_cmpts()'

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::__cxx11::path::_M_split_cmpts()'

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::rename(std::filesystem::__cxx11::path const&, std::filesystem::__cxx11::path const&)'

CMakeFiles/example_step_83_release.dir/step-83/step-83.cc.o:step-83.cc:function Step83::CathodeRaySimulator<2>::checkpoint(): error: undefined reference to 'std::filesystem::status(std::filesystem::__cxx11::path const&)'

make[2]: *** [examples/CMakeFiles/example_step_83_release.dir/build.make:106: bin/step-83.release] Error 1

make[1]: *** [CMakeFiles/Makefile2:8634: examples/CMakeFiles/example_step_83_release.dir/all] Error 2

make[1]: *** Waiting for unfinished jobs....

I will try going with -DDEAL_II_COMPILE_EXAMPLES=OFF. That should also make the build go faster.

David

[Wolfgang Bangerth]

On 2/6/25 10:11, David Montiel wrote:
>
> I tried including the flag -DDEAL_II_CXX_FLAGS="-lstdc++fs" but that still
> didn't work.

It is possible that if you do
export LD_FLAGS="-lstdc++fs"
before calling cmake, it works. But I think your solution is fine for your
purposes too.