You can find here some hacks/tips for low-level programming and other stuff.
Most of these are related to GNU/Linux, examples are given for Debian-based distros, but usualy that doesn't matter.
7 Jan 2021 Enabling color emoticons in dwm
9 May 2020 dwm + HiDpi display
24 Apr 2020 WM-agnostic key bindings
25 Jan 2020 Dealing with GCC warnings in external headers
19 Jan 2020 Why C macros lead to unobvious bugs
12 Jan 2020 How to reapply Telegram message markup on edit
Embox is a RTOS for embedded devices.
It's key feature is a compatibility layer which allows you to run complex POSIX/Linux applications (including Qt/OpenGL and other)