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StateOS is free, extremely simple and very fast real-time operating system (RTOS) designed for deeply embedded applications.


ARM Cortex-M, STM8.


StateOS was inspired by the concept of a state machine. Procedure executed by the task (task state) doesn't have to be noreturn-type. It will be executed into an infinite loop. There's a dedicated function for immediate change the task state (task function).


All documentation is contained within source files, in particular header files.

Gettin started

Building an application for a specific compiler is realised using the appropriate makefile script.


  • kernel can operate in preemptive or cooperative mode
  • kernel can operate with 16, 32 or 64-bit timer counter
  • kernel can operate in tick-less mode
  • implemented basic protection using MPU (use nullptr, stack overflow)
  • implemented functions for asynchronous communication with unmasked interrupt handlers
  • spin locks
  • once flags
  • events
  • signals with protection mask
  • flags (any, all, protect, ignore)
  • barriers
  • semaphores (binary, limited, counting)
  • mutexes with configurable type, protocol and robustness
  • fast mutexes (error checking)
  • condition variables
  • read/write locks
  • memory pools
  • raw buffers
  • message queues
  • mailbox queues
  • event queues
  • job queues
  • timers (one-shot, periodic)
  • hierarchical state machine
  • cmsis-rtos api
  • cmsis-rtos2 api
  • nasa-osal support
  • c++ wrapper
  • support for std::thread
  • all documentation is contained within source files, in particular header files
  • examples and templates are in separate repositories on GitHub
  • archival releases on sourceforge

Supported stdc++ features

  • std::thread, std::jthread, std::stop_callback, std::this_thread, ...
  • std::mutex, std::shared_mutex, std::condition_variable, ...
  • std::binary_semaphore, std::counting_semaphore, ...
  • std::lock_guard, std::unique_lock, std::shared_lock, ...
  • std::future, std::promise, std::assync, ...
  • std::barrier, std::latch, ...
  • std::chrono, ...
  • thread local storage (thread_local)
  • and more ...


This project is licensed under the terms of the MIT License (MIT).