<a target="_blank" href="https://github.com/QuantumLeaps/qpcpp" title="QP/C++ on GitHub"><img style="float:right; clear:right;" src="img/logo_github.png"></a>
To check what's new in QP™/C++, please see @ref history "QP/C++ Revision History". You can also get the latest **QP™/C++ code**, with the recent enhancements and bug fixes, from the <a class="extern" target="_blank" href="https://github.com/QuantumLeaps/qpcpp"><strong>GitHub QP™/C++ repository</strong></a>.
<b>QP™/C++ Real-Time Embedded Framework (RTEF)</b> is a lightweight implementation of the @webref{active-object, Active Object model of computation} specifically tailored for real-time embedded (RTE) systems. QP is both a software infrastructure for building applications consisting of Active Objects (actors) and a runtime environment for executing the Active Objects in a deterministic fashion. Additionally, QP Framework supports @webref{fsm#HSM, Hierarchical State Machines} with which to specify the behavior of Active Objects @ref srs_ref "[ROOM:94], [UML 2.5],[Sutter:10]".
<a href="https://www.state-machine.com/products/qp#CERT" title="QP Cert-Pack"><img src="cert-pack.png" style="float:right; margin:0 20px 0 20px;"></img></a>
The @webref{products/qp#CERT,QP Certification Pack} provides:
- @ref srs_over "Software Requirements Specification" with a good overview of the QP/C++ Framework
- @ref sas_core "Software Architecture Specification" with concise description of QP/C++ architecture
- @ref sds "Software Design Specification" with detailed description of the QP/C++ design.
@section over_goals What does it do?
The main objectives of the QP/C++ RTEF are:
- to provide a modern, event-driven model of concurrency based on the best practices of concurrent programming @ref srs_ref "[ROOM:94], [Cummings:10], [Sutter:10]", collectively known as the @webref{active-object, Active Object (Actor) model of computation}, which is inherently *safer* than the traditional "shared-state concurrency, mutual-exclusion, and blocking" approach based on a conventional Real-Time Operating System (RTOS);
The QP™/C++ Real-Time Embedded Framework (RTEF) is a unique offering on the embedded software market. It provides a modern, reusable **architecture** of embedded applications, which combines object-orientation with the particular model of concurrency, known as @webref{active-object, <strong>active objects</strong>} (actors). This architecture is generally **safer**, more responsive and easier to understand than "free threading" with a traditional Real-Time Operating System (RTOS). It also provides sufficiently high level of abstraction and the right abstractions to effectively apply modeling and code generation to deeply embedded systems.
QP™/C++ is fundamentally an **object-oriented** framework, which means that the framework itself and your applications derived from the framework are fundamentally composed of <a href="https://en.wikipedia.org/wiki/Class_(computer_programming)" target="_blank" class="extern">classes</a> and only classes can have @ref srs_sm "state machines" associated with them.
The behavior of active objects is specified in QP™/C++ by means of @webref{fsm/#HSM, hierarchical state machines (UML statecharts)}. The framework supports @ref sds_sm "manual coding of UML state machines in C++" as well as fully **automatic code generation** by means of the free graphical @webref{products/qm, QM™ model-based design (MBD) tool}.
The QP™/C++ framework can run on @ref exa_native "bare-metal single-chip microcontrollers", completely replacing a traditional RTOS. The framework contains a selection of built-in real-time kernels, such as the cooperative @ref srs_qv "QV kernel", the preemptive non-blocking @ref srs_qk "QK kernel", and the preemptive, dual-mode, blocking @ref srs_qxk "QXK kernel". The QXK kernel <span class="highlight">provides all the features you might expect from a traditional <strong>RTOS kernel</strong></span> and has been specifically designed for mixing event-driven active objects with traditional blocking code, such as commercial middleware (TCP/IP stacks, UDP stacks, embedded file systems, etc.) or legacy software. @ref ports_native "Native QP ports" and ready-to-use @ref exa_native "examples" are provided for major @ref exa_ref_mcu "CPU families".
Even though QP™/C++ offers much higher level of abstraction than a traditional RTOS, it typically outperforms equivalent traditional RTOS offerings both in RAM/ROM footprint and in CPU efficiency. The specific measurements and results are reported in the following @webref{doc/AN_QP_Performance.pdf, Application Note: "QP Performance Tests and Results"}:
The QP Framework is simple to get started, simple to use and simple to build. The numerous provided @ref exa "examples" come with projects for typical embedded toolchains (e.g., GNU, ARM, IAR, etc.). The framework does not impose any proprietary build or configuring procedures or tooling, just simple makefiles and native projects for the demonstrated toolchains. While these are possibly inadequate for really complex projects, experience shows that bigger teams have their own DevOps (e.g., CI/CD) and imposing a particular process is typically counterproductive.
QP™/C++ offers unprecedented, bidirectional @ref trace "traceability" among all work artifacts, which gives teams full visibility from requirements through architecture, design, source code, tests, and back again.
@subsection over_popular Popularity & Maturity
With 20 years of continuous development, over @webref{customers#Customers, 350 commercial licensees}, and many times more open source users worldwide, the QP™ frameworks are the most popular such offering on the market. They power countless electronic products ranging from implantable medical devices to complex weapon systems.
The QP™ real-time embedded frameworks address high-reliability applications across a @webref{customers#Markets, wide variety of markets}, such as medical, consumer, IoT, defense, robotics, industrial, communication, transportation, semiconductor IP, and many others. In each of these application areas, the elegant software architecture and modern design philosophy of QP™ have distinct advantages.
The two editions of the book, @webref{psicc2, <strong>Practical Statecharts in C/C++</strong>} provide a detailed design study of the QP™ frameworks and explain the related concepts.
QP™/C++ is licensed under the sustainable @webref{licensing, dual licensing model}, in which both the open source software distribution mechanism and traditional closed source software distribution models are combined.
If your company has a policy forbidding open source in your product, all QP frameworks can be @webref{licensing#Commercial, licensed commercially}, in which case you don't use any open source license and you do not violate your policy.
If you are developing and distributing **open source** applications under the GNU General Public License (GPL), as published by the Free Software Foundation, then you are free to use the Quantum Leaps software under the <a class="extern" target="_blank" href="https://www.gnu.org/copyleft/gpl.html">GPL version 3</a> of the License, or (at your option) any later version. Please note that GPL requires that all modifications to the original code as well as your application code (Derivative Works as defined in the Copyright Law) must also be released under the terms of the GPL open source license.
If you are developing and distributing traditional **closed source** applications, you can purchase one of @webref{licensing/#Commercial, Quantum Leaps commercial licenses}, which are specifically designed for users interested in retaining the proprietary status of their code. All Quantum Leaps commercial licenses expressly supersede the GPL open source license. This means that when you license Quantum Leaps software under a commercial license, you specifically do not use the software under the open source license and therefore you are not subject to any of its terms.
Please post any **technical questions** to the <a class="extern" target="_blank" href="https://sourceforge.net/p/qpc/discussion/668726"><strong>Free Support Forum</strong></a> hosted on SourceForge.net. Posts to this forum benefit the whole community and are typically answered the same day.
Direct **Commercial Support** is available to the commercial licensees. Every commercial license includes one year of Technical Support for the licensed software. The support term can be extended annually.
