CMake, How it Works (At Three Different Levels)

Want to learn CMake? Visit: cmaketutorial.com/
You've heard about CMake, and want to know how it works? Great! In this video Hans explains how it works at three different levels: the basics, internally, and in practise.
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keasigmadelta.com/blog/cmake-...
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About
At Kea Sigma Delta we enjoy creating awesome stuff using software & electronics, and helping others to do the same.

[@KeaSigmaDelta]

Blooper alert: I said CLion (and even showed the CLion logo), when I meant to say CLang. CLion is an Integrated Development Environment (IDE), whereas CLang is a compiler toolchain (based on LLVM).

[@thepopeofhell3148]

This channel is severely underrated. Would love a vid where you explained the entire process from a C source file to the final executable including terms like toolchain, Cmake and so on

[@KeaSigmaDelta]

Thanks. Interesting idea...

[@jongeduard]

Small note. I would not speak in terms of "Visual Studio", which is the mostly name of the IDE, but the compiler name is actually specifically Visual C++, even though it can build both C and C++ code. Hence the abbreviation MSVC.

[@KeaSigmaDelta]

Thanks for the suggestion. Yes, Visual Studio is the name of the whole package, including the IDE, the compilers, etc.. While MSVC may be more precise, "Visual Studio" is more beginner friendly. People are more likely to have heard of "Visual Studio" than "Visual C++" or "MSVC."

[@Kitsune001Kei]

I love this channel, it's very helpful for me. I'm using CMake with CLion and MSVC compiler (best support for a new features, like C++ named modules, I was using clang before)

[@KeaSigmaDelta]

Great to hear that it's helpful.

[@uuu12343]

TIL its technically possible to explain CMake in a reasonably layman-understandable manner...impressive work I can forsee a potential series of videos on other compilers, compiler toolchains and build systems like ninja, yarn etc etc

[@KeaSigmaDelta]

Thanks.

[@human4566vv]

Thanks, have never worked with build systems like c make, but will definitely check.

[@KeaSigmaDelta]

You're welcome. Glad that the video is helpful.

[@spounka]

I loved the video, very simple and straightforward, no shenanigans of extra info and I like that I would be interested in a similar style video explaining the compilation process from having a source file to an actual binary executable (or library), with all the magic of linkers and preprocessing in between and maybe a video about how compiled binaries are laid in memory? (This stems from me reading about the -fpic flag) Great video, keep up the amazing content!

[@KeaSigmaDelta]

Thanks. I sort of go through the compilation process in the video about toolchains: kzbin.info/www/bejne/b6faYZyFa9qqi80 AFAIK, the layout of a program in memory is platform dependent (i.e,. different OSes organize things differently).

[@eddys5371]

This is very valuable, thank you! Do you have any experience on using SFML? If so could you possibly making a video on setting up a C++ project with SFML. Thank you!

[@KeaSigmaDelta]

Sorry, I've never used SMFL.

[@kirillarionov123456]

Hey, I see you answer questions in comments so I have to ask too. Let’s say there are assets that have to be packaged together with the binary. How would you install them with CMake, and how would you access these assets (relative/absolute paths) from the binary?

[@KeaSigmaDelta]

I use a custom post-build command that adds a symbolic link to the data directory from the directory containing the compiled executable: # Create a symbolic link to the data directory after the project is built add_custom_command( TARGET ${PROJECT_NAME} POST_BUILD COMMAND ${CMAKE_COMMAND} -E create_symlink ${CMAKE_SOURCE_DIR}/Data/ $/Data/) You can do a similar thing for installing, except you'd probably want to copy the data files instead of creating a symbolic link.

[@kirillarionov123456]

@@KeaSigmaDelta thanks for the answer! Though I’ve met some problems myself with similar method. When you start your binary not from the source directory, but rather from the parent or some other directory (running from terminal for example), the assets are then discovered not from directory of the binary, but rather from directory where you run it in terminal. I’ve solved this by prepending argv[0] to the paths of assets. Maybe, I thought, there is more of an elegant solution.

[@KeaSigmaDelta]

@@kirillarionov123456 That's because your program is using the Current Working Directory (CWD) instead of checking what the program's actual directory is. Everything is fine when those two are the same, but it fails the moment those are different. You can get the program's actual path from argv[0]. From there you can get the program directory by chopping off the program's filename. After that, you want to convert it to an absolute path (because the CWD can change), and open all data files relative to that. NOTE: argv[0] may point to a symbolic link, in which case you'll want to follow that link to the program's actual directory.

[@kirillarionov123456]

@@KeaSigmaDelta ye, this is pretty much how I resolved it, thanks!

[@KeaSigmaDelta]

@@kirillarionov123456 Great!

[@diegoaredes2721]

Nice video.

[@KeaSigmaDelta]

Thanks.

[@krzysztofdymanowski8759]

What is the difference between cmake and make, and is there any practical difference?

[@KeaSigmaDelta]

I have a video comparing the two: kzbin.info/www/bejne/lXWylaJ3f8tkbc0 In brief: GNU Make is part of the GCC compiler toolchain, whereas CMake is designed to build software on all platforms, with any C/C++ compiler (e.g., GCC, CLang, Visual Studio, Intel C++).

[@alejandroioio6784]

I don't need to see the video to tell that this guy knows.

[@KeaSigmaDelta]

Hehe. Got that look...

[@fakegamer4815]

Why don't game studios use it to port their games to Linux?

[@KeaSigmaDelta]

I can't speak for any game studio. Nevertheless, a few possible reasons: - Most game studios don't write their own graphics engine, but use an existing one (e.g., Unity , Unreal Engine). Realistically, they can only support platforms that their chosen engine supports - Even if the game engine supports Linux, will there be enough gamers using Linux who would buy their game to justify the expense of porting?

[@rretro2042]

I hate CMake, but needless to say it is a necessary evil.

[@KeaSigmaDelta]

I used to hate it too, but it has improved a lot.