JNA VS crates.io

As far as I understand it, with JNA, all calls into C code go through libffi: https://github.com/java-native-access/jna/blob/master/www/Fu...

This means that every call sets up some libffi data structures and libffi uses this information to perform the native call. Likewise in the other direction for return values. With JNI (and Panama), Hotspot can directly emit the argument/return code a the call, not too dissimilar from what a C or C++ compiler would do. There is still some overhead from maintaining JVM invariants. For example, I think a thread blocked in an FFI call can still participate in a safepoint. But that applies to JNI as well.

If you were prepared to go to the JVM you might try JNA. https://github.com/java-native-access/jna

Other good example, but for Java platform is JNA library. Do not mix it with Java's JNI, which is a bad example of how it could be done.

In case you haven't used it (assuming that you already know about JNI, for comparison) - https://github.com/java-native-access/jna is about as easy as it gets for native interop. Also, as mentioned in another comment, with the Java FFM (Foreign Function and Memory) API already in preview mode, pretty soon, there will be no external dependencies at all, and Java should be able to interop with any language that can talk to C.

The complexity of JNI has given rise to some community-driven libraries that make it simpler to do FFI in Java. Java Native Access (JNA) is one of them. It's built on top of JNI and at least makes FFI easier to use, especially as it removes the need to write any C binding code manually and reduces the chances of memory safety issues. Still, it has some of the disadvantages of being JNI-based and is slightly slower than JNI in many cases. However, JNA is widely used and battle-tested, so definitely a better option than using JNI directly.

This is about calling into any native operating system APIs, as long as they are callable via C or C++ (which these days means "all" operating system APIs).

JNI is somewhat harder to use, because you need custom glue on both sides of the border: Some custom classes in Java and some custom code on the C (and C++) side.

This proposal would remove the need for the glue on the C side and would allow a pure java solution.

Something like this has existed in third-party form for a while as JNA (https://github.com/java-native-access/jna), but now it's going to be built into the JRE itself (if the proposal passes through review)

I use JNA https://github.com/java-native-access/jna , as you can write the entire interface in Java faster as well as easier without the need of messing with the complexities of JNI.

So, be sure to double-check your critical libraries and be sure their alternatives exist in the Rust ecosystem. There’s a good chance the crates you need are available in Rust's crates.io repository.

The previous section was very simple, this section is also very simple but introduces us to cargo which is Rust's package manager, as a JS dev my mind goes straight to NPM.

Now, there has to be a place where all these packages come from. Similar to npmjs registry, where all node packages are registered, stored and retrieved, Rust also has something called crates.io where many helpful packages and dependencies are registered.

Before proceeding, let's check https://crates.io/, the official Rust package registry.

The most thrilling aspect has been the joy of writing the backend. It's like every struct, enum, and method in Rust forms this interconnected Multiverse of code , which you can see in crates.io which is best Documentation experience I Ever Had.

5. Crates.io

When using crates from eg. crates.io, and also things like std and core

Vendoring your packages was very tedious to even remotely get to work with Cargo. I spent a very long time getting Cargo to work together with cargo-local-registry. We vendor crates from crates.io and a custom internal registry.

So this is my question: Which way was the right to find it out? There is no info about this feature on crates.io. I also have no clue what exactly it does and why it is named rwh_05.

Rust does it so much better with https://crates.io . I don't know why Go can't (or won't) do something similar.