macOS/clang support

[mincequi]

Hey there,
thanks for this nice lib.
I am trying to compile it on macOS with its shipped clang. Unfortunately, this is not working, since some c++20 features are missing within clang and libc++: std::ranges::for_each, std::ranges::copy_if, std::stop_token.
https://en.cppreference.com/w/cpp/compiler_support/20#C.2B.2B14_library_features

My question is, will you consider compatibility with macOS and clang?
If yes, are there any plans on this in the near future?
Or would you accept PRs fixing macOS/clang compilation?

Thanks a lot!

[AlexInLog]

Hey!
Yeah, I know about this problem. To be honest, I don't have such a plans, because...
While std::ranges is pretty easy to fix, I'm really not sure about std::stop_token - some internal logic relies on this heavily. If you can provide some good idea how to adapt it for Apple Clang - you are welcome =) One more thing: concepts - RPP uses them everywhere but Apple Clang has "partial" support for it...

Or would you accept PRs fixing macOS/clang compilation?

Yeah, I'm fully open to any PRs if it would not be too overcomplicated.

[mincequi]

Hey there,
thanks for your feedback.
Although, i am pretty experienced with C++ in general, i would rate my knowledge in newer aspects (C++17 and later) somewhat lower. When I will find an easy way to adapt, i will keep you posted.
However, i believe, that clang and/or apple will adapt to C++20 in the near future.
So, any effort from me (and you) might be pointless, that's why i completely understand your decition.

I will continue using rxcpp for now, but i am pretty open to switch over to your lib as soon as it is usable on macOS.

Anyway, awesome effort from your side and keep going. I will have an eye on this :)

[AlexInLog]

Hi @mincequi ,

Yeah, I see. But I’m not sure about your hopes related to Apple/Clang. I can suggest you using gcc or clang (not Apple) instead of Apple Clang if it is applicable in your case

[mincequi]

Hi @victimsnino ,

according to the link which i posted above, this is not related to Apple's clang, but the general clang/libc++ combination.
I also tried the stock clang v15, however without success.
Unfortunately, GCC is not an option, because it is very painful to use on macOS and Homebrew. :(

[AlexInLog]

Sounds strange, because I have ubuntu + clang combination in CI and it works fine
-- The CXX compiler identification is Clang 11.0.0

Are you sure that your clang was stock clang not Apple Clang? I mean, for example, by default if you are trying to use "gcc" on mac, it is just kind of symlink to Apple Clang. For example:

➜  ~ which gcc
/usr/bin/gcc
➜  ~ gcc --version
Apple clang version 14.0.0 (clang-1400.0.29.102)
Target: x86_64-apple-darwin21.6.0
Thread model: posix
InstalledDir: /Library/Developer/CommandLineTools/usr/bin

In this case to call "real installed gcc" I need to use more specific binary:

➜  ~ gcc-12 --version
gcc-12 (Homebrew GCC 12.2.0) 12.2.0
Copyright (C) 2022 Free Software Foundation, Inc.
This is free software; see the source for copying conditions.  There is NO
warranty; not even for MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.

I believe, there can be something similar for clang

[AlexInLog]

Double-checked with "not apple" clang on mac - same errors like for Apple Clang. Looks like "not apple" clang on mac uses libc++ while "ubuntu" clang uses libstdc++ (which has all implemented features)

[mincequi]

Ok, maybe this narrows down to libstdc++ vs libc++

[AlexInLog]

I will try to think about possible W/As.

BTW:

Unfortunately, GCC is not an option, because it is very painful to use on macOS and Homebrew. :(

Why? Just do

brew install gcc@12
export CC=gcc-12
export CXX=g++12

and you can build anything with gcc =)

[mincequi]

Yeah, true, but Homebrew packages are usually precompiled with clang/libc++.
For GCC I would have to rebuild everything using GCC ;)
https://docs.brew.sh/Custom-GCC-and-cross-compilers

However, looking forward to your W/As :)

[AlexInLog]

Ohhhh, I see, it makes sense =) Looks like I'm not so experienced Mac user =)
Ok, then I would check what I can to do with that