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Comment by kennywinker | Hacker News Reader

Just one data point, but: I'm currently learning about embedded microcontrollers. The standard starting point for this is arduino, which is C/C++ based, so there is a strong pull towards C++ already. But I really wanted to avoid C/C++, and I spent a long time researching alternatives. Rust was one of the most mature for MCUs, but a) it's not very mature and b) you have to pick an MCU with a lot of flash memory as even the smallest rust binary is >100kb. For reference, one of the chips I've been testing out for this project has 127kb of flash. This evening I loaded on a medium-sized C++ project and it took just 24kb.

So that's what's preventing ME from using rust instead of C++

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which one generated a 100k binary? I see it running on an uno right here, which has less than 100k https://github.com/avr-rust/arduino

Were you using zinc or some other project as the base? I figure it is an arm cortex * in your case.

I was using the standard rust compiler, plus a bunch of articles on thinning rust binaries. Best I managed was about 80kb after three or four layers of thinning. That link is pretty interesting! The Rev3 uno has 32kb flash, so someone has found a way to thin the binaries enough to fit on an MCU. Cool.. now if only I knew how they did it!

see how zinc does it https://github.com/hackndev/zinc

EDIT: Zinc seems to not have been updated in awhile I'm not sure what the current status is of other mcu efforts. I bet some of the other rust folks can elaborate.

The size of a binary statically-linking libstd and targeting a desktop OS has nothing to do with the size of a binary targeting a bare-metal microcontroller where you use only libcore. If you compile for a MCU target with MCU-style code, your code size will be in the same ballpark as the equivalent C++.

How different is a desktop OS when you're doing syscalls directly (or through a tiny libc) from an embedded OS?

See your post sounds like a say so story without data behind it.

There's really no way to trim down the rust binaries??

There are a bunch of articles on trimming. I think I managed to get it down to like 80kb before I gave up.

There absolutely is; the smallest known Rust binary is 151 bytes.

How about a smallest real application that doors something useful? Say, basic networking on the level of static pages like uhttpd. (Used in many routers.) Or a busybox ash equivalent at least.

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