Embedded Template Library (ETL)

Overview

John Wellbelove's header-only C++ template library, designed as an STL alternative for embedded systems where dynamic allocation, exceptions, and the full STL are forbidden. Provides fixed-size containers, queues, callbacks, state machines, and the C++ idioms that make firmware readable without runtime cost.

Benefits

• Zero dynamic allocation by design — sizes are template parameters
• Works in -fno-exceptions builds
• Header-only — drops into any CMake project
• Production-tested across automotive, defense, and industrial firmware

Limitations & Risks

• Template-heavy code can hit compiler memory limits on large projects
• Documentation is functional but less polished than mainstream STL
• API is 'STL-like, not STL-identical' — minor friction for developers used to std::

Recommended Actions

Adopt for any modern C++ embedded project that wants STL-style containers without dynamic allocation. Pair with #77 Modern C++ (C++20/23) for Embedded as the language baseline.

Additional Notes

Pairs with #77 Modern C++ for Embedded. Alternatives include EASTL and modm — ETL has the broadest active production footprint of the three.

References & Links

• https://www.etlcpp.com/
• https://github.com/ETLCPP/etl