When C/C++ is still better than Rust?
Introduction
In the previous note: "Why I prefer rust for embedded systems" I talked about some distinc Rust features that makes software easier to me, specially embedded software. In this article I will expand that talk but about its drawbacks.Madurity
C/C++ has been existing for a very long time. This has lead to very mature community with templates for many use cases and bugs solutions, some of them are slightly unknown for hobbiest which is the larger base of Rust users. In the field of embedded system, since tooling is still too immature, software engineers have to do a lot of work to get equivalent tooling of what already exist in C, and then it leads to dark corners about what the language can express and what it cannot. This becomes even more terrible when you have to deal with custom chips or newer hardware, because you can not expect that Rust compiler can run on that hardware and since Rust compiler is very strict about hardware access, the there is not other option than use wrap Rust code into unsafe Rust (unsafe {//code}), but then this cause not only that you cannot use Rust features, but unsafe Rust is not simpler to write than C code. I dare to say it is even harder. Also, you will need to rewrite a lot of code to make it suitable for the hardware. Then, there is no gain of use Rust in that case, unless you are using Software than someone else already wrote and tested with a large team of tester/engineers.
Performance
A little bit of this has been said in why I do prefer Rust for embedded systems entry. C/C++ parallel execution in embedded system are done with RTOS. And since C/C++ community is more mature than Rust, RTOS solutions are also maturer than RUST ones. For that reason in large projects or project were performance is critical, then C/C++ are better programming language options. But that is not all the matter. In Linux foundation, not much time ago a movement of rewritten a large portion of legacy code into Rust has lead to some interesting founds. Rust version are much slower than C counter side. One could argue that is just a think of correction some algorithms. But that is not entirely true. You cannot expect to do a translation C to Rust one line per line, that is impossible and it makes no sense. Then it becomes essentially a problem of Rust capacity to translate that code. When software is translated from one language to other, it is quite common that some dark corners of languages comes to light and then are appears in bugs and performance issues that are not easy to solve.