For MCU code, it's best practice to statically allocate all memory. If you do need dynamic allocation, it's better to use either fixed size pool allocators, or

For MCU code, it's best practice to statically allocate all memory. If you do need dynamic allocation, it's better to use either fixed size pool allocators, or allocate only pools. For performance critical code running on a more powerful system with an OS, it's still good to stick with static allocation, or malloc and free only during initialization time. Over the last decade I've written firmware for space ships, self driving cars, and autonomous aircraft, and I've never needed more than an allocate only pool or an O(n) LRU cache data structure. I've written plenty of software that was hard on the heap, but rarely does memory need to be freed during runtime, and it's rare to need raw pointers in C++ when writing such code. Ideally, your "firmware" is written in a way that abstracts away the target hardware enough that it's basically just weird software. Then, you can unit test it, and even run linters and memory sanitizers on it.