Comment by AndyKelley

> If you wanted to match Ghostty's performance in Rust, you'd need to use unsafe in order to use these memory mapping APIs, then you'd be in the exact same boat.

Yea, but not for all the parts — being able to isolate the unsafe and build abstractions that ensure certain usage parts of the unsafe stuff is a key part of high quality rust code that uses unsafe.

In this case though I think the emphasis is on the fact that there is a place where that code should have been in Rust land, and writing that function would have made it clear and likely avoided the confusion.

Less about unsafe and more about the resulting structure of code.

> Actually you'd be in a worse boat because Zig is safer than unsafe Rust

Other people have mentioned it but I disagree with this assertion.

Its a bit simplistic but I view it this way — every line of C/Zig is unsafe (lots of quibbling to do about what “unsafe” means of course) while some lines of rust are unsafe. Really hard for that assertion to make sense under that world view.

That said, I’m not gonna miss this chance to thank you and the Zig foundation and ecosystem for creating and continuously improving Zig! Thanks for all the hard work and thoughtful API design that has sparked conversation and progress.

I don't buy your theory that a Rust terminal would need to directly use mmap to deliver matching performance. In fact I doubt Ghostty's author would endorse this claim either, they've never tried any alternatives, they tried this and it works for their purpose which is a long way from other ways wouldn't work or would all be slower or whatever.

[dead]

Please don’t get defensive and spread silly FUD. You can be proud of what you’ve accomplished without feeling sad that a different language has strengths that yours doesn’t.

Calling unsafe mmap APIs not only is unlikely to run into the corner cases where unsafe Rust is tricky to get right, there’s “millions” of crates that offer safe APIs to do so and it’s fundamentally not hard to write it safely (it would be very hard to write it to have any issues).

And fundamentally I think Rust is much more likely to be easier to get high performance because the vast majority of safe code you write is amenable to the compiler performing safe optimizations that Zig just can’t do regarding pointer aliasing (or if it does brings all the risks of of unsafe Rust when the user annotates something incorrectly).