libc VS pottery

> I absolutely don't see how this is a problem with semver,

Strange to not see it. Semver promises to solve dependency hell. In the example everyone correctly followed the sevmver and the app is broken by a dependency hell issue.

> it is not the responsibility of semver to tell a language how packages should be isolated and loaded. That is a problem of a) the language and b) dependency resolution in the package manager.

So semver only works for "good" languages?

> Bundler, by design, does not allow the above, instead having a flat, consistent vision of dependencies.

Ok, so what happens with the app when packages managed by Bundler get fragmented by depending on an incompatible version of sub-dependency (commons-logging 1.1.1 vs 2.0.1 as in the example)?

Also note, even for languages and tooling supporting multiple library versions loaded side by side, there are scenarios where things break.

For example, the "libc apocalypse" situation in Rust https://github.com/rust-lang/libc/issues/547

Here after the "libc" module released a major version, the definition for the `void` C type in two versions of the lib are considered by the compiler as two different types, resulting in breakages everywhere around the library ecosystem.

There are also scenarios for dynamic languages / runtime errors.

> None of this is the responsibility of semver. In fact, semver would help the language provide tooling to detect that kind of "hey this instance is from foo-1.0 but you're trying to consume it in foo-2.0".

And what's next after it detected the dependency hell? It's too late and the person suffering is not in the position to fix it. You have to upgrade to "authentication 1.1.2" for security compliance, because the version 1.1.1 has known vulnerabilities. But that breaks the application, because the maintainer of the lower level dependency "commons-logging" follows semantic versioning.

The promise was to prevent dependency hell, not to detect it.

Quoting the ticket and reiterating the point of my first comment above:

Once again, the point of this ticket is to:

    Remove the false promise that SemVer solves dependency hell by simply increasing major version.

Even if coexistence of multiple library versions is supported, there are scenarios where things break.

For example, the "libc apocalypse" situation in Rust https://github.com/rust-lang/libc/issues/547

Here after the "libc" module released a major version, the definition for the `void` C type in two versions of the lib are considered by the compiler as two different types, resulting in breakages everywhere around the library ecosystem.

There are also scenarios for dynamic languages / runtime errors in statically typed languages.

My main problem with the current SemVer spec, is that it does not mention multiple lib versions problem, and promises the dependency hell issues can be solved simply by updating major version number. Thus encouraging to break backward compatibility freely.

Also note, it's not the case that SemVer is intended only for languages supporting multiple library versions. The SemVer is a product of Ruby community, and Ruby has a global namespace for classes and unable to have several versions of a lib simultaneously.

In 2000s they were breaking compatibility left and right, neglecting elementary compatibility practices. If you were working on an application, practically every time when you update dependencies, something would break.

So (in 2011 ?) they came out with this "manifesto" (Why such a big name? This scheme of versioning was well established in linkers and sonames of all Unix-like systems for decades - it goes back to at least 1987 paper "Shared Libraries in SunOS").

It's a good thing SemVer acknowledges finally that compatibility is a serious matter. Only that it's better to discourage compatibility breakages. An in cases when it's really needed (I agree such cases exists), there are things to take care of in addition to simply increase major version num.

The libc crate exposes system C APIs in Rust code, and is used by the compiler and standard library. It also does not contain any C code. See for yourself.

Ok, what if we are sure that our C code would use a given version of malloc/free only to allocate memory (are we ever sure about anything like that is out of the scope of the article)? Well, in this case we are brave enough to use libc crate in our rust code:

Port libc. I recommend using bindgen for this.

While looking at the libc crate and its build script, I don’t quite understand when or how the crate’s libc definitions link to the build target’s actual libc.

For what it's worth, there's been discussion of this not only for glibc on Linux but also for BSDs which take many more liberties with API and ABI compatibility to keep their technical debt low. I can't summarise the years of discussion here but I encourage anyone interested to read through https://github.com/rust-lang/libc/issues/570

In answer to what appears to be a misunderstanding about Rust:

> Its foreign function interface seems particularly poorly implemented. The official Rust documentation suggests the use of the external third-party libc library (called a 'crate' in Rust parlance) to provide the type definitions necessary to interface with C programs. As of the time of writing, this crate has had 95 releases. Contrast this with Ada’s Interfaces.C package, which was added the language in Ada 95 and hasn’t needed to change in any fundamental way since.

Rust's libc crate isn't third-party, it's first-party, developed by the Rust project itself: https://github.com/rust-lang/libc/ . It's also not just for "type definitions necessary to interface with C programs"; here's the first heading and first paragraph of its README:

"libc - Raw FFI bindings to platforms' system libraries"

libc provides all of the definitions necessary to easily interoperate with C code (or "C-like" code) on each of the platforms that Rust supports. This includes type definitions (e.g. c_int), constants (e.g. EINVAL) as well as function headers (e.g. malloc).

The fact that this library contains low-level type definitions for every platform that Rust supports explains why it's had more than one release: new platforms get added, platforms add new interfaces, and platforms change the definitions of existing interfaces.

> It lacks basic features necessary for the task, like bitfields, and data structure packing.

The latter is achieved via the built-in `repr(packed)` attribute (https://doc.rust-lang.org/nomicon/other-reprs.html#reprpacke...) and the former is provided by the bitflags crate: https://crates.io/crates/bitflags (while unlike libc this does not live under the rust-lang org on Github, it does live under its own org which appears to be populated exclusively by Rust project team members).

It came up in this issue in the libc crate. The initializer for a static has to be const, which is why the issue submitter wanted it. He couldn't use lazy_static or once_cell, common patterns in Rust, since he was later using the static in a unix signal handler (which must be async signal safe).

Pottery - The page for open hash map reads "Documentation still needs to be written. In the meantime check out the examples."

"Using macros" is a broad description that covers multiple paradigms. There are libraries that use macros in combination with typed pointers and functions that take void* parameters to provide some degree of API genericity and type safety at the same time (e.g. stb_ds and, as you mentioned, my own CC). There are libraries that use macros (or #include directives) to manually instantiate templates (e.g. STC, M*LIB, and Pottery). And then there are libraries that are implemented entirely or almost entirely as macros (e.g. uthash).

The prototype of CC used this mechanism to provide a generic API for types instantiated via templates (so basically like other container libraries, but with an extendible-_Generic-based API laid over the top of the generated types). This approach has some significant advantages over the approach CC now uses, but I got a bit obsessed with eliminating the need to manually instantiate templates.

I think it's common for C programmers to roll their own. I did the same [0].

I went pretty deep into composable C templates to build mine so it's more powerful than most. The containers can handle non-bitwise-movable types with full C++-style lifecycle functions and such, and the sort algorithms can handle dynamic and non-contiguous arrays (they are powerful enough to implement qsort() [1], which is more than I can say for any other C sort templates I've seen.) My reasoning for the complexity at the time was that any powerful container library is going to be reasonably complex in implementation (as anyone who's looked at STL source code knows), so it just needs to be encapsulated behind a good interface.

I'm not so sure that's true anymore. These sorts of simpler libraries like the one linked here definitely seem to be more popular among C programmers. I think if people are using C, it's not just the C++ language complexity they want to get away from, but also the implementation complexity of libraries and such. There's a balance to be had for sure, and I think the balance varies from person to person, which is why no library has emerged as the de facto standard for containers in C.

[0]: https://github.com/ludocode/pottery

Yes! The include style of templates in C is way better than the old way of huge macros to instantiate code. The template code can look mostly like idiomatic C, it interacts way better with a debugger, it gives better compiler errors... everything about it is better and it's finally starting to become more popular.

I've open sourced my own C template library here:

https://github.com/ludocode/pottery

Not only does it use the #include style of templates, but it actually makes the templates composable. It takes this idea pretty far, for example having a lifecycle template that lets you define operations on your type like move, copy, destroy, etc. This way the containers can fully manage the lifecycles of your types even if they're not bitwise movable.

There's also this other more popular C template library, one that tries to more directly port C++ templates to C but with a lot less features:

https://github.com/glouw/ctl/

This article doesn't really make it clear but the merge sort discussion is specifically about glibc's implementation of qsort(). glibc's qsort() and Wine's qsort() are the only ones I know of that use merge sort to implement qsort(). Most implementations use quick sort.

I recently did my own benchmarking on various qsort()s since I was trying to implement a faster one. The various BSDs and macOS qsort() are all faster than glibc at sorting integers and they don't allocate memory:

https://github.com/ludocode/pottery/tree/master/examples/pot...

Of course sorting is much faster if you can inline the comparator so a templated sort algorithm is always going to be faster than a function that takes a function pointer. But this does not require C++; it can be done in plain C. The templated intro_sort from Pottery (linked above) is competitive with std::sort, as are the excellent swensort/sort templates:

https://github.com/swenson/sort