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* Add ranges * Initial Hugo setup * Work in progress * Added selection for local or remote site * Updated to 'light' theme * Changed to using Hextra Hugo theme * Changed to using Hextra Hugo theme * Changed to Hextra Hugo theme * Change to Hextra Hugo theme * Updated Hugo setup. * Updated Hugo setup. # Conflicts: # docs/releases/_index.md * Work in progress * Added new fonts Added new documentation * Latest documentation updates * Latest documentation updates # Conflicts: # docs/containers/array.md # docs/containers/array_view.md # docs/containers/array_wrapper.md # docs/containers/bip_buffer_spsc_atomic.md # docs/containers/bitset.md # docs/containers/indirect_vector.md # docs/containers/vector.md # docs/getting-started/compilers.md * Added bloom_filter markdown doc * Added more documentation Updated CSS for light and dark modes * Fixed some menus Added mode documentation files * Updated CSS rules Added badges to home page Added uniqur_ptr + pool tutorial * Fixed formatting on the home page markdown Modified light amd dark code formatting * Updated unique_ptr-with-pool * Added container and shared message tutorials * Updates to documentation * Added const_multimap * Updated source-formatting.md * Added initial raw text files form Web site editor * Innore coverage build directory * Exported raw text documentation files from the web site editor * Hugo updates * Added Hugo intalation and markdown descriptions * More addition to the documentation * Added closure.md and updates to delegate.md * Added format.md * Added documentation for etl::delegate_observable, etl::function, Base64 codec * Added io_port documentation * Added basic_format_spec * Added documentation for string_stream and string utilities. * Added more documentation Updated the documentation CSS * Added documentation for clocks, day, duration * Added more documentation for chrono classes Updated callouts * More chrono documentation * Completed chrono documentation * Maths functions documentation * Completed maths documentation * Completed maths documentation * Completed maths documentation * Completed maths documentation * Added multiple documentation files * Added iterator.md * Added debug_count.md and versions.md * Added debug_count.md and versions.md * Added more documentation * More documentation * Added some design pattern documentation Modified some of the layout files Modified the About documentation * Converted more documentation pages Modified the site CSS * Added more documentation Moced some documentation files to new directories * Added more documentation Tweaks to CSS * Added callback_timer_deferred_locked documentation * Added callback_timer_locked documentation * More documentation updates * More documentation updates * More documentation updates * New documentation files. Harmonised file name format * New documentation files. * Multiple document updates * Multiple document updates * Final conversion of web pages * Updates before PR * Updates before PR * Updates before PR # Conflicts: # docs/blog/_index.md * Final pre PR updates * Updates to message framework documentation * Renamed directory * Fix spelling * Added author and date to blog files Moved documentation files merged from development * Fixed 'Description' typo * Fix typos # Conflicts: # docs/IO/io_port.md # docs/containers/sets/const-multiset.md # docs/containers/sets/const-set.md # docs/maths/correlation.md # docs/maths/gamma.md * Renamed two files to lower case * Minor renaming * Added author and date * Updated callout on bresenham_line.md Added support for showing the ETL version on the documentation first page, by copying the version.txt file as a hugo asset. Updated the Python 'update_release.py' to copy 'version.txt' * Replace space in filename with hyphen. Added more information to hugo-commands.md * Replace space in filename with hyphen. Added more information to hugo-commands.md # Conflicts: # docs/getting-started/view-the-docs-locally/hugo-commands.md * Added a link to pseudo_moving_average.md * Updated title pages for groups * Fixed missing 404 for non-existent pages * Fixed coordinate variable names in the 'Calculating the intersection' example --------- Co-authored-by: Roland Reichwein <Roland.Reichwein@bmw.de> Co-authored-by: John Wellbelove <john.wellbelove@etlcpp.com> Co-authored-by: John Wellbelove <john.wellbelove@etlcpp.co.uk>
132 lines
7.7 KiB
Markdown
132 lines
7.7 KiB
Markdown
---
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title: "Embedded Template Library"
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weight: 998
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type: hextra-home
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---
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<div class="not-prose badges">
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<div>
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<img src="https://img.shields.io/github/v/release/jwellbelove/etl" alt="release">
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<img src="https://img.shields.io/github/release-date/jwellbelove/etl?color=%231182c3" alt="date">
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<img src="https://img.shields.io/badge/c%2B%2B-98/03/11/14/17/20/23-blue.svg" alt="standard">
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<img src="https://img.shields.io/badge/license-MIT-blue.svg" alt="license">
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<img src="https://img.shields.io/github/contributors-anon/ETLCPP/etl" alt="contributors">
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<img src="https://img.shields.io/github/forks/ETLCPP/etl?style=flat" alt="forks">
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<img src="https://img.shields.io/github/stars/ETLCPP/etl?style=flat" alt="stars">
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</div>
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<div>
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<img src="https://github.com/ETLCPP/etl/actions/workflows/msvc.yml/badge.svg?branch=master" alt="CI MSVC">
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</div>
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<div>
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<img src="https://github.com/ETLCPP/etl/actions/workflows/gcc-c++11.yml/badge.svg?branch=master" alt="CI GCC 11">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/gcc-c++14.yml/badge.svg?branch=master" alt="CI GCC 14">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/gcc-c++17.yml/badge.svg?branch=master" alt="CI GCC 17">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/gcc-c++20.yml/badge.svg?branch=master" alt="CI GCC 20">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/gcc-c++23.yml/badge.svg?branch=master" alt="CI GCC 23">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/gcc-syntax-checks.yml/badge.svg?branch=master" alt="CI GCC syntax">
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</div>
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<div>
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<img src="https://github.com/ETLCPP/etl/actions/workflows/clang-c++11.yml/badge.svg?branch=master" alt="CI Clang 11">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/clang-c++14.yml/badge.svg?branch=master" alt="CI Clang 14">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/clang-c++17.yml/badge.svg?branch=master" alt="CI Clang 17">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/clang-c++20.yml/badge.svg?branch=master" alt="CI Clang 20">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/clang-c++23.yml/badge.svg?branch=master" alt="CI Clang 23">
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<img src="https://github.com/ETLCPP/etl/actions/workflows/clang-syntax-checks.yml/badge.svg?branch=master" alt="CI Clang syntax">
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</div>
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<div>
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<a href="https://github.com/ETLCPP/etl/actions/workflows/coverage.yml"><img src="https://github.com/ETLCPP/etl/actions/workflows/coverage.yml/badge.svg" alt="coverage"></a>
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<a href="https://www.codacy.com/manual/jwellbelove/etl"><img src="https://api.codacy.com/project/badge/Grade/3c14cd918ccf40008d0bcd7b083d5946" alt="Codacy"></a>
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</div>
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<div>
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<a href="https://www.etlcpp.com/sponsor.html"><img src="https://img.shields.io/static/v1?label=Sponsor&message=%E2%9D%A4&logo=GitHub&color=%23fe8e86" alt="Sponsor"></a>
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</div>
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</div>
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## Version
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This documents version **{{< version >}}**.
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## Motivation
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C++ is a powerful language for embedded systems development, with templates offering a great deal of flexibility and type safety. While the C++ Standard Library provides a wealth of well-tested functionality, it’s often not well suited to environments with strict deterministic behavior and limited resources.
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In many embedded applications, dynamic memory allocation is discouraged or outright prohibited, making standard STL containers and many other components impractical or unusable.
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What’s needed is a template library specifically designed for embedded systems — one that allows developers to define fixed or maximum sizes for containers and other objects at compile time. Additionally, since many older (but still in use) embedded toolchains lack full support for standards beyond C++03, it's valuable to have access to a library that backports select features from later versions of the C++ Standard Library.
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## About the ETL
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The Embedded Template Library (ETL) is not intended as a full replacement for the C++ Standard Template Library (STL), but rather as a complementary solution tailored specifically for embedded systems.
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**Its design goals include**
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- Providing a set of containers with fixed or maximum sizes defined at compile-time.
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- Offering APIs that closely resemble those of the STL, enabling familiar and consistent usage.
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- Maintaining compatibility with C++98 while implementing many features introduced in later standards
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(C++11/14/17/20/23/26) wherever possible.
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- Ensuring deterministic behavior, which is critical in real-time and resource-constrained environments.
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- Introducing additional components and utilities useful in embedded contexts but absent from the STL.
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- The ETL avoids dynamic memory allocation entirely; the heap is never used. All non-intrusive containers have a fixed capacity, allowing memory requirements to be fully determined at compile-time. This makes the ETL ideal for lower-resource embedded applications where predictability, performance, and memory control are essential.
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The library is compatible with any compiler that supports C++03 or later.
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Help on integrating the ETL with your project may be found here.
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## Key Features of the ETL
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- Actively Maintained: Developed and maintained on GitHub since 2014.
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- Open Source: MIT licensed.
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- No STL Dependency: Designed to operate independently of the C++ Standard Template Library.
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- No Dynamic Memory Allocation: All storage is allocated either at compile-time or on the stack; heap usage is entirely avoided.
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- RTTI and Virtual Functions: No runtime type information (RTTI) is required. Virtual functions are used sparingly and only when strictly necessary.
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- Header-Only Library: All functionality is provided via header files; No separate compilation needed.
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- Fixed-Capacity Containers: Offers STL-like containers with fixed or maximum capacity, plus additional non-standard container types.
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- Cache Efficiency: Containers use contiguous memory layouts for optimal cache performance.
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- Compact Codebase: Shared base classes (based on type) help reduce overall container code size.
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- Compile-Time Features:
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Templated compile-time constants
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Template-based design pattern base classes (e.g., Visitor, Observer)
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Type-safe smart enumerations
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Type-safe typedefs and constants
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- Embedded System Frameworks:
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Message routing
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Finite state machines
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Task scheduling
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- C++11 Backports:
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Implements many C++11 features (type traits, algorithms, containers) for use in C++03 environments.
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- Utilities:
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CRC calculations (8, 16, 32 & 64-bit)
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Checksums and hash functions
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- Variants (type-safe unions)
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- Extensive template support utilities
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- Robust Error Handling: Configurable error checking using asserts, exceptions, error handlers, or no checks; user’s choice.
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- Thoroughly Tested:
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Over 10,000 unit tests
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Tested with Visual Studio 2022, GCC 12, and Clang 14
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Continuous integration via GitHub Actions.
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- Readable and Well-Documented: Clean, maintainable source code with clear documentation.
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- Support: Free email support available. A Slack group is available. Paid support on request.
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- Archived: A snapshot of the ETL is preserved in the Arctic Code Vault for long-term digital preservation.
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## Support the ETL
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Maintaining the ETL can take a lot of man-hours of work, but unfortunately it doesn't pay the bills. When I have to take on paying work, the ETL gets a lot less attention. So if you have found the library is an important component in your work and you would like to help out, then please consider by supporting the project.
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---
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[**Is the ETL free?**]({{< relref "is the ETL free.md" >}})
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---
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Any help porting the library to work under different platforms and compilers would be gratefully received.
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I am especially interested in people who are using Keil, IAR, Green Hills, TI Code Composer etc, bare metal
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or RTOS, and DSPs.
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Many thanks.
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John.
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