I also recommend taking a look at Zephyr RTOS [1]. I've been using it in production for almost a year, and no major complaints so far. There seems to have supp

I also recommend taking a look at Zephyr RTOS [1]. I've been using it in production for almost a year, and no major complaints so far. There seems to have support for POSIX threads and BSD sockets, but I don't use them, so I can't tell you if they are production-ready or not. [1]: https://www.zephyrproject.org/ https://www.zephyrproject.org/