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> However I fail to see how it's worse than most other multithreaded languages. C++, JVM languages, Go, Python - they all don't provide a lot of support for wri

> However I fail to see how it's worse than most other multithreaded languages. C++, JVM languages, Go, Python - they all don't provide a lot of support for writing correct thread-safe programs. Swift/Objective-C might even have an edge compared to some of them, due to providing dispatch queues in the standard library - which are fairly easy to reason about, as shown in the article. A couple corrections: - Dispatch Queues are not a part of the Swift standard library. They are part of Grand Central Dispatch which is almost always present where Swift is present but is actually a separate project. - JVM languages, well specifically Java at least, do have synchronization primitives built-in. It's part of the Java language spec. You can mark any method as synchronized for instance and it will automatically be mostly thread-safe.

Matthias247 8y ago
Thanks for adding it. I was actually aware of both things. While Java has some builtin syntax (synchronized) for mutexes, as well as the notify/wait methods on Objects, I don't see them as a big step forward in avoiding concurrency issues. Programmers still need to be aware that they need to use those constructs, which is in most cases already the Nr 1 issue. The next step is using them correctly. The JVM ecosystem has a huge number of libraries and APIs that aim to make concurrency easier (java.util.concurrent, RxJava, Quasar, etc). But all those must first be found, and then used correctly. Rust on the other hand will remind users that something is missing. And Go at least shows the a bit higher level channels first, instead of mutexes.
- kjeetgill 8y ago
  While it's true that much of the hard work of not writing data races is still in the users hands it's important to remember that Java having a memory model and specification for locks/volatiles is a VAST improvement over the same situation in most other languages. It expressly defines what operations do and do not imply a causal relationship, guarantees things like no word tearing on volatile longs, that variables can't "logically" be optimized out of existence in the presence of out of thread writes. It's actually pretty great in practice.
raphlinus 8y ago
JVM has two additional advantages over Swift (sorry for repeating) - an actual memory model, and data races can cause logic errors but not the full undefined behavior of LLVM languages.
pjmlp 8y ago
You can implement synchronized in a couple of lines in Swift, thanks to trailing lambdas.

Matthias247 8y ago

Thanks for adding it. I was actually aware of both things. While Java has some builtin syntax (synchronized) for mutexes, as well as the notify/wait methods on Objects, I don't see them as a big step forward in avoiding concurrency issues. Programmers still need to be aware that they need to use those constructs, which is in most cases already the Nr 1 issue. The next step is using them correctly. The JVM ecosystem has a huge number of libraries and APIs that aim to make concurrency easier (java.util.concurrent, RxJava, Quasar, etc). But all those must first be found, and then used correctly. Rust on the other hand will remind users that something is missing. And Go at least shows the a bit higher level channels first, instead of mutexes.

kjeetgill 8y ago
While it's true that much of the hard work of not writing data races is still in the users hands it's important to remember that Java having a memory model and specification for locks/volatiles is a VAST improvement over the same situation in most other languages. It expressly defines what operations do and do not imply a causal relationship, guarantees things like no word tearing on volatile longs, that variables can't "logically" be optimized out of existence in the presence of out of thread writes. It's actually pretty great in practice.

raphlinus 8y ago

JVM has two additional advantages over Swift (sorry for repeating) - an actual memory model, and data races can cause logic errors but not the full undefined behavior of LLVM languages.

pjmlp 8y ago

You can implement synchronized in a couple of lines in Swift, thanks to trailing lambdas.