Most large C code bases aren’t really written in C. They’re written in an almost-C that includes certain extensions and undefined behavior. In this case, it uses inline assembly (an extension) and manipulating pointers as integers (undefined behavior).

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throwaway17_17 5 hours ago | parent [-]

While I’m always thankful when people give the broad perspective and context in a discussion, which your comment does. The specifics of this particular project’s usage of almost-C is not something I could have quickly figured out, so thanks. For such a large program, an to be as old as Qt is at this point, I find it impressive and slightly amazing that it has in some sense self-limited its divergence from standard C. It would be interesting to see what something like SQLite includes in its almost-C.

	▲	wat10000 4 hours ago \| parent [-]
		The more portable a project is, the less weird stuff it’s likely to do. The almost-C parts become more of a headache the more OSes and compilers you support. This seem pretty tame, and I’d expect SQLite to be similar. I work on some projects that only support a single OS, compiler, and CPU architecture and it’s full of dependencies on things like the OS’s actual address space (few 64-bit archs use all 64 bits).