How does emio compare to fmtlib for embedded systems?

emio is designed specifically for embedded systems with a much smaller binary footprint—about 38 times smaller—and uses result objects instead of exceptions for deterministic error handling. However, fmtlib is more mature and widely adopted, so choose based on priorities between size and ecosystem support.

Can emio be used with Arduino?

emio can be used with Arduino if the compiler supports C++20, but it's optimized for bare-metal and RTOS systems. Check your Arduino toolchain for C++20 compatibility and ensure the library fits within memory constraints, as it avoids heap usage.

How to integrate emio into a CMake project?

Use CMake's FetchContent to declare the emio repository and tag, then make it available as shown in the README. Alternatively, download the single header file or use the Conan package for simpler inclusion in your build system.

Does emio support floating-point formatting?

The README doesn't explicitly detail floating-point support, but given its design for embedded I/O, it likely handles basic types. Refer to the API documentation for specifics on supported data types and formatting options.

How to handle errors with emio's result objects?

emio functions return result objects that you must check using methods like .value() or .has_value(). Handle errors by inspecting these results, similar to std::expected, to maintain exception-free operation in embedded code.

Is emio suitable for real-time operating systems like FreeRTOS?

Yes, emio is designed for RTOS-based systems with heap-free operation and deterministic error handling, making it a good fit for real-time environments. However, verify compatibility with your specific RTOS constraints and scheduling requirements.

Open-Awesome

emio

MITC++0.9.1

A safe, fast, and tiny character I/O library for bare-metal and RTOS embedded systems with high-level formatting and low-level control.

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188 stars8 forks0 contributors

What is emio?

emio is a C++ character input/output library tailored for bare-metal and RTOS-based embedded systems. It provides safe, fast, and memory-efficient APIs for formatting, scanning, and low-level I/O operations, solving the problem of bulky or exception-throwing libraries in resource-constrained environments.

Target Audience

Embedded systems developers working on bare-metal or RTOS platforms who need a lightweight, deterministic I/O library without exceptions and with minimal binary footprint.

Value Proposition

Developers choose emio for its exceptionally small binary size, exception-free error handling, and dual high-level/low-level API design, which are specifically optimized for embedded constraints unlike general-purpose C++ libraries.

Overview

A safe and fast high-level and low-level character input/output library for bare-metal and RTOS based embedded systems with a very small binary footprint.

Use Cases

Best For

Reducing binary footprint in memory-constrained embedded applications
Implementing formatted output without exceptions on bare-metal systems
Building RTOS-based devices needing both high-level and low-level I/O control
Creating compile-time validated formatting for embedded firmware
Replacing std::format or fmtlib in environments where size and exceptions are problematic
Developing embedded systems with deterministic error handling requirements

Not Ideal For

Desktop or server applications where binary size and exception handling are not primary concerns
Projects that mandate exception-based error handling for consistency with existing codebases
Environments using compilers without full C++20 support, such as older embedded toolchains
Teams needing extensive third-party integrations or community plugins beyond core I/O functionality

Pros & Cons

Pros

Minimal Binary Footprint

Approximately 38 times smaller than fmtlib, significantly reducing memory usage for embedded devices, as highlighted in the README.

Exception-Free Error Handling

Returns result objects instead of throwing exceptions, ensuring deterministic behavior crucial for bare-metal and RTOS systems.

Dual API Flexibility

Provides both high-level formatting/scanning similar to std::format and low-level writer/reader APIs, allowing adaptable use in various embedded scenarios.

Compile-Time Capabilities

APIs can be used at compile-time, enabling metaprogramming and validation for advanced embedded firmware development.

Cons

Beta Status Risks

The library is in beta, meaning potential for bugs, incomplete features, or breaking changes as noted in the README's milestone link.

Limited Ecosystem

Compared to mature libraries like fmtlib, emio has fewer integrations, tools, and community resources, which could slow development.

C++20 Dependency

Requires a compiler with C++20 support, which might not be available in all embedded toolchains, limiting adoption in legacy environments.

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