Documentation for building C++ examples

[c-joly]

Hi @costashatz, here is a new issue about the JOSS review openjournals/joss-reviews#6771
These comments are based on the Ubuntu 22.04-arm64 installation with the one line installation script

1- First, I successfully ran the Hello World example in Python, and I was happy to see my first robot in the graphical interface 😃

2- However, building the C++ example was a little bit more difficult. I did not find any building instructions on the FAQ page, so I started to manually compile the cpp example, which was a bad idea! Then, I figured out there is a CMake example in the source of the GitHub, but I did not see any reference to it in the doc (or maybe I scanned too fast the doc page and I missed it?)

3 - Finally, the example was not exactly working out of the box since cmake was not able to find robot_dart, magnumand corrade. I had to manually set the CMAKE_PREFIX_PATH environment variable:

• export CMAKE_PREFIX_PATH=/opt/magnum:/opt/robot_dart
• then, the "classical" building procedure with cmake works fine:
  • mkdir build
  • cd build
  • cmake ..
  • make (eventually with -j4, -j8 depending on the computer capabilities...)
• Then, I successfully adapted the CMakeList.txt to build an other example in headless and graphical mode.
• Can you put instructions in the installation doc to add the export CMAKE_PREFIX_PATH command in the .bashrc / .profile / .zshrc, like you did for the PYTHONPATH, PATH... environment variables?
• Can you add a page in the doc that is linked to the CMakeList.txt example and provide the standard procedure to build it and adapt the CMakeList.txt to other examples? This could be very helpful to users like me who did not use cmake for a long time (but I think I am more the target of the Python version 😂)

[c-joly]

Haha, I should be blind or maybe I was too tired the day I wrote this issue... There is actually some explanations at the very end of the FAQ! 😅

However, it does not mention the possible problems that can occur if cmake cannot find the different packages. Can you please add a comment about the environment variable CMAKE_PREFIX_PATH?

[costashatz]

@c-joly feel free to re-open the issue if #215 did not fix this :) Thanks again!