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Comment by dlivingston | Hacker News Reader

C++ modules seem like one of those things worth staying far, far away from. I wish they worked well because it would be a huge boon to modernizing C++. But from what I've seen, it's a dumpster fire. The spec is too broad and ill-defined. The compilers have gone to herculean lengths to implement it regardless, and MSVC is the only compiler with full support (for a C++20 feature, mind you). [0]

Libraries aren't implementing it. There's no `cargo`-like tooling for installing modules (AFAIK).

Can the C++ committee revert or refine the modules spec? Has anything like that been done before?

[0]: https://arewemodulesyet.org/tools/

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In JS, modules were a massive improvement pretty much from day one. They were fairly quickly adoped and worked well. It's been a huge quality-of-life improvement, especially with the latter addition of import maps.

I just wish we'd get working, well-supported modules like that for C++. I tried them once, but support was abysmal and I won't touch them again until they work nicely everywhere.

To be fair, only thanks to JavaScript/TypeScript compilation and polyfills to AMD and CJS pseudo modules approach, only recently has nodejs supported ES6 modules without having to deal with switches.

I've been using modules in nodejs for a very long time. What sucked initially was that you had to use a command line flag at first, and it still sucks that you have to use the mjs extension. Still, those are minor issues compared to the issues modules face in C++. And in browsers, modules worked nicely almost from the start, and since import maps you don't even need to use any kind of build system amymore.

Likewise I have been using C++ modules for my C++ hobby coding since VS 2019 prototype introduction, despite all the warts.

Nowadays, with exception of header units, VC++ and clang alongside MSBuild and CMake/ninja are pretty much usable for anyone that is able to stick to a specific platform.

I don't consider still fighting with build tools options in 2025 to make a pleothora of npm dependencies happy to run under nodejs a minor issue.

Yes, reverting has happened. extern templates have been removed.

Only because outside EDG, no one else has bothered to implement them.

Another example is the GC introduced in C++11, likewise no one made use of it.

VC++, clang and GCC have implemented modules, granted there are still bugs to iron out.

export template extern still exists.

I completely disagree. I am currently working on a large C++ project with modules and the developer experience is amazing.

As always, the problems are always with 3rd party libraries that require special handling when compiling, but that was always the case.

We could have off-the-shelf tooling as good as Cargo etc today, if it weren't for those special cases. Myself I just use a simple script.

> As always, the problems are always with 3rd party libraries that require special handling when compiling, but that was always the case.

I'm not sure what you mean here. Could you explain please?

The only extra work I had to do in this modules-only project was not related to modules at all, but rather when integrating some third-party libraries, for a diversity of reasons.

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