Rust vs C++ for Embedded Systems – Safety Meets Performance

In the world of embedded systems, the question arises more and more often: Rust or C++? Both languages promise efficient and high-performance programming of embedded systems, but their approaches differ fundamentally. This guide will help you make an informed decision about which language is best suited for your next embedded project. It highlights the advantages of Rust (such as built-in memory and thread safety guarantees) over C++, which relies on optional developer discipline. This way, you can develop safe and efficient systems without unnecessary detours.

Overview & Comparison

C++ is the long-standing top dog in the embedded field. For decades, C++ (and its predecessor C) has dominated the programming of embedded systems. There are good reasons for this: C++ offers direct hardware access and fine-grained control over memory and resources. In areas with tight resources and strict real-time requirements, C++ has made a name for itself. Add to that a huge ecosystem of toolchains, microcontroller SDKs, frameworks, and existing code. Many billions of lines of legacy code run reliably in vehicles, industrial plants, or IoT devices – this treasure cannot simply be replaced overnight.

Rust is the newcomer with a safety promise. Compared to C++, Rust is still the new star in the embedded sky. Made popular by the Mozilla community, Rust brings a breath of fresh air: the language offers compile-time memory safety and fearless concurrency, i.e., memory safety and concurrency without a garbage collector and without sacrificing performance. Rust’s compiler enforces clean code. So forget buffer overflows, null pointer dereferences, or data races – Rust’s borrow checker won’t even let such errors compile. At the same time, Rust generates highly optimized machine code that can keep up with C++ in performance tests. No wonder Rust regularly appears as one of the most popular languages in developer surveys.

Proven vs. modern – what do you rely on? While C++ relies on the experience and discipline of developers (“Don’t do anything unsafe, watch your pointers!”), Rust takes a stricter approach: safety by design. This means that many sources of error are excluded by the language itself. C++ can certainly be used safely with modern C++ standards, smart pointers, const-correctness, static analyzers, and strict code reviews. But all these are optional measures that require extra work. Rust, on the other hand, comes with a safety net and modern language features out of the box. The comparison boils down to this: Rust vs C++ in the embedded context is built-in guarantee versus optional precaution. Next, we’ll look at the details of these differences.

Detailed Comparison of Key Aspects

Below, we dive deeper and compare Rust and C++ in the areas of memory management, concurrency, type & error handling, mutability, and tooling. You’ll see how Rust’s ownership model prevents buffer overflows and use-after-free errors, and how zero-cost abstractions enable high performance without a garbage collector.

Memory Management and Ownership

In C++, responsibility for memory lies with you as the developer. You can allocate memory with new or malloc and must free it with delete or free, or you use modern approaches like std::unique_ptr or std::shared_ptr, which use RAII to automatically clean up memory. In theory, you can avoid memory problems this way, but in practice, small mistakes quickly lead to memory leaks, double-frees, or buffer overflows. C++ does not provide built-in checking of pointers or array bounds; it’s up to your discipline (or additional tools) to find such errors. A large proportion of notorious security vulnerabilities (estimates say ~70% of all security bugs) are due to memory problems in C/C++.

Rust’s approach is radically different: through the ownership model and the borrow checker, the compiler ensures that memory is handled safely. Every variable has exactly one owner and a clear lifetime. When an object goes out of scope, Rust automatically frees the memory (without a garbage collector, but deterministically when leaving the valid scope). Double freeing is impossible, and every reference must be valid as long as it is used; otherwise, the program won’t even compile. Buffer overflows are also avoided, as accesses to arrays or Vec are bounds-checked by default (in release builds, Rust optimizes this away, but keeps safety checks during development). In short: Rust’s compiler takes on the guardian role that in C++ is left to you and external tools. The result: significantly less time debugging memory errors and a reassuring feeling that certain bugs simply cannot happen.

Concurrency

C++ offers powerful tools for parallelism with threads, mutexes, atomics, etc. However, the compiler can hardly protect you if multiple threads access the same resources simultaneously. Data races (race conditions) and deadlocks are notorious pitfalls in multithreaded C++ programs. It takes a lot of care and know-how to implement threading safely in C++. There are libraries and patterns (e.g., actor model, std::future/std::async, or the newer std::jthread), but ultimately it’s up to you to synchronize access and protect shared data correctly.

Rust has thread safety built directly into its type system. The language defines traits like Send and Sync, which determine whether a type can be moved or shared between threads. Types that cannot be safely used in parallel (e.g., those that are mutable but lack a mutex) cannot be transferred to other threads unless you explicitly make it unsafe. In addition, the borrow checker ensures that only one thread or owner can access a mutable variable at a time. If you want multiple accesses, you must consciously use synchronization primitives like Mutex or Arc (atomically reference-counted pointer); these are also safe abstractions in Rust that prevent misuse (e.g., std::Mutex wraps access in a lock object that is automatically released when it goes out of scope). Data races are detected by Rust at compile time and the build is refused. This doesn’t mean you can never have a deadlock or logical error, but many common multithreading errors are nipped in the bud by Rust. The Rust community calls this “fearless concurrency” because you can dare to use concurrency without constantly fearing hidden race conditions.

Train in Rust and C++

Answer tricky quiz questions about Rust and C++ in the Cyberskamp Quiz. Here you can test your knowledge, learn new things, and truly understand both programming languages in depth.

Discover Cyberskamp Quiz

Types, Null, and Error Handling

C++ is statically typed and very flexible (templates, overloading, etc.). But there are well-known pitfalls: the obvious example is the null pointer. In C++ (as in C), a pointer can be nullptr. If you forget to check for this and access it, you get a crash. C++ has no built-in Option for “no value”; you either rely on discipline (“check for nullptr”) or helper types like std::optional or smart pointers. It’s similar with errors: C++ offers exceptions, but in embedded systems, exceptions are often rejected for performance or space reasons. Many embedded teams disable exceptions and prefer to work with return codes (e.g., 0 for success, -1 for error) or special values, which can easily be ignored. This means error handling in C++ is often left to the developer. You have to be strict yourself, check every function for errors, or use try-catch blocks properly if exceptions are allowed.

Rust’s type system is more modern and stricter. A big advantage: Null does not exist. Instead, Rust has the Option type, which can be Some(T) or None. You must handle this case explicitly, or it won’t compile. For errors, there is the Result<T, E> type, which is either Ok(T) (result) or Err(E) (error). You are forced to deal with both cases, either through match statements or conveniently with the ? operator, which returns early from the function with the error result. In summary, Rust enforces solid error handling, leading to more robust programs. Things like integer overflows are also detected in Rust in debug mode (but not in release mode for performance reasons, unless you enable it). The type system also offers powerful constructs like algebraic data types (enums with variants) and pattern matching, which allow states and errors to be represented more elegantly than with traditional enum+switch in C++. Overall, Rust’s strict type system helps catch many errors during development, which in C++ often only show up during testing or, in the worst case, at the customer’s site.

Mutability and Constness

In C++, variables are mutable by default. Only if you explicitly write const does something become immutable. In practice, many developers do not consistently use const, which means variables can be unintentionally changed. C++’s const system is also sometimes tricky (keyword: const correctness). You have to know exactly where const is (left/right of the type) to understand what is constant. Lack of constness can lead to bugs, e.g., if a value is accidentally overwritten.

Rust turns this principle around: variables are immutable by default. If you want to change a variable, you must mark it with mut. This leads to a more deliberate programming style, as you carefully consider what really needs to be changed. Everything else remains read-only, which in turn helps the compiler optimize and guarantee thread safety. Mutability in Rust is something you explicitly opt-in to, whereas in C++ it’s opt-out. In addition, Rust’s concept of immutability by default also applies at a higher level. For example, multiple references (&T) to a resource are fine as long as none of them is mutable. If a reference is mutable (&mut T), it must be unique. These rules prevent a whole class of errors. For you as a developer, this means a period of adjustment at first, but you quickly notice that with fewer hidden changes in the code, behavior becomes much more predictable.

Tooling & Ecosystem

C++ has existed since the 1980s, so there is a wide variety of tools, but no unified solution. In C++ projects, you encounter Makefiles, CMake, meson, or other build systems, plus vcpkg, Conan, or even manual handling of libraries. Setting up a development environment can be complex, and managing dependencies is sometimes tedious. For analysis and debugging, the C++ world has powerful tools (e.g., Valgrind for runtime memory analysis, AddressSanitizer/ThreadSanitizer for uncovering problems, clang-tidy for linting). These tools are powerful but often external components that you have to use deliberately. On the plus side, almost every microcontroller manufacturer offers out of the box support for C/C++, whether through a bundled GCC compiler, IDEs like Keil/ARM or IAR, and sample code and drivers in C/C++. Here, the mature ecosystem of C++ shows its strength, as there is a solution or library for almost every problem, though not always of consistent quality.

Rust shines with a modern, integrated tooling experience. The centerpiece is Cargo, Rust’s package manager and build system in one. With a single tool, you create a new project, add dependencies, build, test, and package your program, including automatic fetching of libraries (crates) from the central repository crates.io. This makes setting up a new project in Rust feel very unified. Rust also comes with standard tools: rustfmt for consistent formatting, clippy for linting (which gives helpful code quality hints), and excellent compiler error messages, which may scare newcomers but are incredibly educational. The Rust ecosystem for embedded has grown rapidly in recent years. There is embedded-hal as a hardware abstraction layer, many microcontrollers are supported by community projects (e.g., stm32f4xx-hal for STMicro electronics or nrf-hal for Nordic chips). However, it must be said that Rust’s embedded ecosystem is still much younger. Not every exotic architecture has an optimized Rust compiler or official vendor support yet. Sometimes pioneering work is needed, such as writing your own unsafe drivers or integrating existing C libraries. But the Rust community is extremely active and helpful; new crates are constantly appearing, and even major players (see below) are contributing to the ecosystem. All in all, Rust offers a modern developer experience where much works “out of the box,” while in C++ you sometimes have to spend a bit more time tuning your tools before you can be productive.

Challenges & Use Cases

No comparison would be complete without a look at the practical challenges and exemplary use cases. Why isn’t everything already written in Rust if it sounds so great? Here we look at the learning curve, ecosystem maturity, integration into existing projects, and use cases from safety-critical systems to IoT devices.

Learning Curve and Transition

The learning curve of Rust is undeniably steeper than that of C++, especially for developers coming from the C/C++ world. The concept of ownership and borrowing requires a shift in thinking. At first, it can be frustrating when the compiler keeps rejecting your code, even though you “know what you’re doing.” Many Rust beginners joke: “My code doesn’t compile, so it can’t have a bug.” Because the compiler is so strict, it feels like you’re fighting against it at first before you become productive with it. This takes time and patience. Teams that have been developing in C++ for years must therefore invest in training if they want to introduce Rust. In other words: a C++ expert does not become a Rust expert overnight. This initial hurdle is something that slows the rapid adoption of Rust in the embedded field. However – and this is important – the effort is often worth it. After a while, you start “thinking” in Rust and avoid many mistakes from the outset. Productivity can increase because you spend less time in the debug loop. Still, for short, tight projects or teams with little time for upskilling, C++ remains the more convenient path for now.

Train in Rust and C++

This course will teach you the fundamentals of Rust in a way that will stick, so you can apply them directly to your own projects. Check out udemy and sign up for the course.

To the course

Ecosystem Maturity and Community

As mentioned, C++ has decades of head start. The ecosystem around Rust in the embedded context is growing rapidly but is still immature in some niches. For example, you may have a special sensor or a proprietary protocol for which there has long been a C library. The likelihood is high that you won’t (yet) find this ready-made for Rust. Then you have the following options:

• write it yourself in Rust

• bind the C library via an FFI interface

• or stick with C++

In safety-critical fields, there are also certification processes (e.g., MISRA standard in automotive) that are currently mainly designed for C/C++. Rust is working on such topics (there are efforts to use Rust for MISRA, for example), but it’s a path that still needs to be taken. On the other hand, community support is remarkable. The Rust embedded community (working groups, forums, Discord) is very active, and many problems can be quickly solved by asking the community. With each year, the ecosystem matures further; what was experimental in 2018 may be stable and well-documented by 2024. Nevertheless, if you start a project today, you should check whether all the components you need are available in Rust or at least bridgeable. For standard microcontrollers (ARM Cortex-M family, RISC-V, etc.), Rust is ready, but in very exotic cases, C/C++ may still be the only realistic choice.

Integration into Existing Codebases

Realistically, many of us are sitting on existing code. Maybe you have a large C/C++ codebase that has been maintained for years. A complete rewrite in Rust would be expensive and risky. The good news is that Rust works wonderfully with C. Through the Foreign Function Interface (FFI), Rust components can be integrated into C/C++ and vice versa. Some projects start this way: safety-critical modules are rewritten in Rust and then connected to the existing system, while the rest remains in C/C++. This way, you can gain experience step by step without risking everything. Still, this integration is an effort, as you have to define interfaces, carefully handle unsafe blocks, and possibly adjust the build system. C++ may have fewer hurdles here at first, as it works almost seamlessly with C and can even include C code directly. Rust requires caution at FFI boundaries (memory passing, structures, ABI conventions). But it is doable and already being practiced (for example, in the Linux kernel, new drivers are implemented in Rust that coexist with the rest of the C kernel). So if you have a lot of legacy C code, you could initially use Rust as a supplement. If, on the other hand, you have the choice to start from scratch, are not bound by legacy, and can start a greenfield project, there is much to be said for making Rust the main language and not building up C++ at all.

Use Cases: From Safety to IoT

Rust’s features make it particularly attractive for safety-critical applications. Wherever a crash or undetected bug could have catastrophic consequences, such as in automotive, aerospace, medical technology, Rust is being closely examined. Large organizations and companies are already experimenting with Rust. For example, a major automotive manufacturer has announced plans to use Rust in future control units to eliminate memory errors. In 2024, the US government officially recommended using memory-safe languages like Rust for safety-critical software. Such developments show the trend that Rust is being taken seriously when it comes to reliability.

Security is also playing an increasing role in the IoT sector and with connected devices. IoT devices are often accessible via the network and thus a target for attacks. A buffer overflow in a smart light bulb may sound trivial, but it can provide an entry point into the network. Rust helps minimize such vulnerabilities. In addition, IoT devices are usually resource-constrained. Rust’s zero-cost abstractions are ideal here because you can write high-level code that remains lean and fast. Projects like the real-time operating system TockOS (written in Rust) show that Rust is practical even on small microcontrollers. At the same time, tens of millions of IoT gadgets still run on plain C code, which won’t disappear anytime soon. C++ (or C) still dominates here, also because many vendor SDKs are based on it. But especially startups and new projects in the IoT sector are eyeing Rust to have secure firmware from the start that needs fewer patches.

In summary, Rust is finding its way especially where safety, stability, and maintainability are more important than the last bit of fine-tuning or the sheer familiarity of existing solutions. C++ remains strong where proven solutions, broad support, and existing know-how are decisive.

Conclusion & Recommendations

When to stick with C++? If you have a running project with a lot of existing C++/C code and limited resources for a technology switch, C++ remains a solid path. The language is mature, your team knows it inside out, and all tools from compiler to debugger are established. Even if your target platform is very specialized (such as a rare microcontroller or a DSP without Rust support) or if you rely on libraries that only exist in C/C++, you are (still) better off with C++. In projects with very hard real-time requirements (where absolutely deterministic runtime is required), some developers feel more comfortable with C/C++ because they have every CPU cycle in their own hands, although Rust is theoretically on par here, but is new and unfamiliar. In short: Stick with C++ if you rely on its established base and a switch would bring more risk than benefit.

When to choose Rust? However, if you are starting a new project in the embedded field and have the freedom to choose the language, Rust is an extremely attractive option. The initial investment in learning pays off with fewer errors and more solid code in the long run. Especially in applications where reliability over years is crucial (e.g., devices that need to be maintained via firmware updates or systems that must run 24/7 without crashing), Rust plays to its strengths. Compile-time safety saves you countless debugging hours and potential security incidents. Your code remains maintainable because many dangerous patterns are not allowed in the first place, making it easier for future developers (or yourself in two years) to work with. Rust is also a great choice if you value a modern developer experience, as the ecosystem, tools, and community are simply fun and promote good practices. Especially for smaller embedded teams without a dedicated QA department, Rust can act like a built-in guardian angel that watches over many things.

Rust vs C++ doesn’t have to be an either-or for all eternity. Both worlds can coexist. Maybe you write safety-critical parts in Rust and use C++ for the rest, getting the best of both worlds. The technology decision should always fit the project. Rust is not a cure-all, but in many scenarios, it is a clear step forward in terms of safety and efficiency. C++, on the other hand, has a success story that you don’t build on for no reason.

One last tip: Whatever you decide, stay open to new things. The embedded world is evolving, and who knows, maybe Rust will be as commonplace in a few years as C++ is today. Trends already show that memory-safe programming is the future. In the end, your choice should help you build safe and high-performance embedded systems without detours. Good luck!

If you want to learn Rust, I can highly recommend this course on udemy: Rust: The Complete Developer's Guide

Curious for more? Sign up for my newsletter to get the template and not miss any updates.