qProtothreads is a fork of Protothreads, an extremely lightweight stackless threads designed for severely memory constrained systems.

qProtothreads provides a blocking context on top of an event-driven system, without the overhead of per-thread stacks. The purpose of qProtothreads is to implement sequential flow of control without complex state machines or full multi-threading.

Main features:

* No machine specific code - the qProtothreads library is pure C
* Does not use error-prone functions such as longjmp()
* Very small RAM overhead - only two bytes per qProtothread
* Provides blocking wait without full multi-threading or
  stack-switching
* Freely available under a BSD-like open source license    

The qProtothreads library is released under an open source BSD-style license that allows for both non-commercial and commercial usage. The only requirement is that credit is given.

The qProtothreads library was written by Adam Dunkels adam@sics.se with support from Oliver Schmidt ol.sc@web.de. Arduino port by Ben Artin ben@artins.org

More information the original Protothreads at homepage: http://www.sics.se/~adam/pt/

The original code lives at: https://gitlab.com/airbornemint/arduino-protothreads

The latest qProtothreads code lives at: https://github.com/qnimble/arduino-qprotothreads

Documentation can be found in the doc/ subdirectory.

Two Arduino example programs are included to illustrate the use of qProtothreads:

• Blink: Blinks the on-board LED.
• Button: Turns the on-board LED on an off with a push button.

Both examples are based on stock Arduino sample code, modified to work with qProtothreads.

qNimble, Jan 27 2023

Baseed on work by Ben Artin, July 15 2020

Based on work by Adam Dunkels, 3 June 2006