Comment by Wololooo | Hacker News Reader

Comment by Wololooo | Hacker News Reader

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I know this is not your main point, and you touched briefly on it but, cmake is absolutely terrible.

It is supposed to make the building process more straight forward and painless but what it brings to the table is

* Weird bugs: In one version of cmake would return the python version that I had to be 0.16 (????) and the only fix was to update the cmake version

* Messy Structure: Under the guise of giving freedom to the person designing their build with no real enforcement of any rules, in any way, people can write their own absolute craptastic version of cmake scripts which really really is going to make you lose your mind (mind you some people leverage it but it is the exception not the rule)

* Opaque process: Due to the fact that the structure can be messy you are never really quite sure of what it is doing and which compile flags are effectively fed to the compiler as well as sometimes totally ignoring the library you explicitly ask it to use and trying to find another one...

OK maybe this is a bit superlative, but unfortunately for me, reflects well my experience with using cmake and feels like an extra item between me and getting things working painlessly... But I might have been doing it wrong.

I understand this perspective if considering CMake in the past (i.e. pre 3.0 or so), but in my experience CMake today is much nicer (albeit definitely still not without its flaws). Specially for the points you mention:

* “Weird bugs”: I suspect CMake wasn’t finding the version of Python you wanted because your find_package command was just finding a different version first. This is much easier to debug today by using —-debug-find-pkg=Python, which will print all the places it searches Python for and what it finds. You can then modify your find_package invocation as appropriate to find the Python you really want to use.

* Messy structure: yes, unfortunately I’ve also seen my fair share of nightmare-inducing CMake files.

* Opaque process: here I actually quite disagree. In my experience I’ve found it super easy to modify things like compiler flags (just use target_compile_options, or add_compile_options for directory wide options). And what made a big difference was using Ninja as the generator (I also use Ninja on Windows), which makes it super easy to view the final compiler commands that will actually be invoked. CMake is essentially a compiler that emits Ninja on the backend, and several times it’s been invaluable to confirm in the generated Ninja code what is actually being invoked.

CMake is definitely not perfect, but it’s much better than what it used to be! It’s ultimately a perfect match for C++ (both extremely powerful, configurable, hamstrung with decades of backwards compatibility, terrible ergonomics, etc.).

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