Tag: C++

When writing a freestanding application, it’s generally necessary for the firmware engineer to handle runtime initialization. Even when a library like newlib includes a rudimentary implementation of crt0.o, initialization is a very application-specific process owing to the need to initialize hardware, memory, and other loading tasks.

In this essay, we examine the current and historical implementation of executable initialization, finishing with a minimal implementation usable with firmware applications.

Note: Most firmware applications need to address the initialization of .data and .bss from nonvolatile memory. That is not addressed in this essay.

Bazel is one of the least terrible build systems out there. It can handle large codebases, mixed languages, and cross-platform builds like a champ. Unfortunately, it suffers from rather poor documentation with an enterprise Java codebase that is a nightmare to decipher.

One of the features I’ve been trying to make use of are linkstamps. The idea behind linkstamps is to embed information such as the Git commit identifier into the resulting binary, providing direct traceability for deployed binaries. Unfortunately, regarding this feature, Bazel suffers from the common documentation anti-pattern where they describe what an option is, not what it does.

Inline functions are a notable feature of both C and C++. By exposing the source file to the implementation of a function, they allow a variety of optimization techniques that wouldn’t be possible if it had to call out to a subroutine in a different file (at least without link-time optimization).

However, despite the common syntax, the C and C++ languages implement them in very different ways. While C++ takes a “user friendly” approach and automatically manages the manipulation of multiple implementations, C requires a more manual approach. As a result, inline functions are less common in C and mixed language code, generally using the nuclear option of declaring them static.