GitHub - an-dr/microlog: A lightweight, universal logging library in C. Just two files. Compatible with C++, embedded projects, and most major compilers. Covered by unit tests.
microlog - Extensible and configurable logging library for embedded and desktop applications
Easy to use - simple API, works out of the box
Advanced filtering and log levels per topic or output
Thread-safety via external locking injection
Customization - only data you need
Extensible - add your own features via public API, set of predefined extensions
Support for embedded systems static allocation, small size
Easy to install two files for copy-paste and support for many build systems
For everyone - C and C++ support, works with any compiler, any platform, commercial or open-source use
In the default configuration it looks like this:
Picture 1 - default configuration: no time, long default levels, source location, no topics, no colors...but in can be very minimalistic :
Picture 2 - short levels, no colors, no time, no source location... or feature-rich:
Picture 3 - time, custom prefix for MsgID, custom syslog levels, topics, source location, colorsThe project is based on the following core principles:
Universal for embedded and desktop applications
No feature - no code for compilation
Shallow learning curve, works out of box
No dependencies
Two files for core functionality.
Extensions as recipes for your own features.
Table of Contents
microlog - Extensible and configurable logging library for embedded and desktop applications
Key Capabilities Unique to microlog
Quick Start
1. Install
Option 1 - Sources:
Download a Source Package from
Add sources to your system manually
Option 2 - CMake Package (recommended CMake > 3.15.0):
Download a CMake Package from
Specify the install location: Specify package storage cmake -B./build -DCMAKE_PREFIX_PATH="~/MyCmakePackages" or
Set microlog_DIR variable with path to the package microlog_DIR=~/microlog-1.2.3-cmake
Use in your project:
find_package(microlog1.2.3REQUIRED) add_executable(example_packageexample.cpp) target_link_libraries(example_packagePRIVATEmicrolog::microlog) target_compile_definitions(micrologPRIVATEULOG_BUILD_COLOR=1) # configuration# Or use a user-defined configuration header `ulog_config.h`:# target_compile_definitions(microlog PRIVATE ULOG_BUILD_CONFIG_HEADER_ENABLED=1)# target_include_directories(microlog PRIVATE path/to/directory/containing/ulog_config.h)Option 3 - Meson Package:
Download a Meson Package from
Copy the content to MyMesonProject/subprojects
Add to your dependencies:
add_global_arguments('-DULOG_BUILD_COLOR=1', language: ['cpp', 'c']) # configuration# Or use a user-defined configuration header `ulog_config.h`:# add_global_arguments('-DULOG_BUILD_CONFIG_HEADER_ENABLED=1', language: ['cpp', 'c'])# And add include directory where ulog_config.h is located:# add_global_arguments('-Ipath/to/directory/containing/ulog_config.h', language: ['cpp', 'c']) exe =executable( meson.project_name(), src, include_directories: include, dependencies: dependency('microlog'), )Option 4 - Meson Wrap File:
Download the wrap file from
Place microlog.wrap in your MyMesonProject/subprojects/ directory
Add to your dependencies as in Option 3
Option 5 - CPM:
Download CPM (
https://github.com/cpm-cmake/CPM.cmake
)
Add microlog to your projects CMAKE file:
include(cpm/CPM.cmake) CPMAddPackage("gh:an-dr/[email protected]") target_link_libraries(${PROJECT_NAME}PUBLICmicrolog::microlog) target_compile_definitions( micrologPRIVATEULOG_BUILD_COLOR=1) # configuration# Or use a user-defined configuration header `ulog_config.h`:# target_compile_definitions(microlog PRIVATE ULOG_BUILD_CONFIG_HEADER_ENABLED=1)# target_include_directories(microlog PRIVATE path/to/directory/containing/ulog_config.h)2. Use
#include"ulog.h"intmain() { ulog_info("Hello, World"); return0; }Output:
INFO src/main.cpp:4: Hello, World 3. Extend
Add missing functionalities via API or use predefined extensions. See
.
Advanced Usage
User Manual in doc/features.md
- detailed information about the available features.
- Optional add-ons that use only the public API to enhance functionality.
See the example for more features in action: example/main.cpp
.
Contributing
Contributions are welcome! Please read the
for details, I tried to keep it simple.
Comparison with log.c
microlog started as a fork of
(~150 lines, 3.3k stars) but evolved into a fundamentally different architecture (~2,500 lines) optimized for embedded systems and advanced filtering. Thanks to compile-time feature stripping, unused features are excluded from the build—so a minimal microlog configuration can match log.c’s footprint in both size and performance.
Core Differences
rxi/log.c: Minimalist and ready to use. Fixed footprint, 6 levels, simple callbacks. microlog: Compile-time feature selection. Configurable footprint, 8 renameable levels, multi-dimensional filtering.
Featurelog.cmicrologPhilosophySimple-to-use, Minimalist for average useSimple-to-use, extensible and configurable for diverse needsConfigurationColor, verbosity✅ Compile-time feature selection + optional runtimeRuntime ConfigurationOnly verbosity✅ Verbosity, color, time, prefix, source location, topics (Disablable feature)Zero-Overhead DisableArguments still evaluated✅ True no-op with ULOG_BUILD_DISABLEDLog Levels6 fixed8, runtime renameable (e.g., syslog)FilteringGlobal + per-callbackPer-output + per-topic + globalTopics/SubsystemsManual prefixes✅ Full support with filtering per topic and routingOutput RoutingAll outputs get all logs✅ Route topics to specific or all outputsMemoryStatic✅ Static or dynamic (user choice)Build SystemsManual integration✅ CMake, Meson, CPM packagesPlatform HelpersDIY✅ FreeRTOS, Zephyr, ThreadX, pthread, Win32TL;DR:
When to choose log.c: Small projects needing basic logging with minimal setup.
When to choose microlog: Same scenarios, as default setup is just as simple.
Plus: embedded systems, multi-subsystem applications, or projects requiring fine-grained control and advanced filtering.
Key Capabilities Unique to microlog
1. Multi-Dimensional Filtering - Per-output AND per-topic levels:
ulog_topic_add("Credentials", secure_file_only, ULOG_LEVEL_TRACE); ulog_topic_add("Network", ULOG_OUTPUT_ALL, ULOG_LEVEL_DEBUG); ulog_output_level_set(ULOG_OUTPUT_STDOUT, ULOG_LEVEL_ERROR); // Console: errors only2. True Zero-Overhead Disable - Arguments not evaluated:
ulog_info("Result: %d", expensive()); // With ULOG_BUILD_DISABLED=1 → ((void)0)3. Custom Log Levels - Redefine all 8 at runtime:
ulog_level_descriptorsyslog= {ULOG_LEVEL_7, {"DEBUG", "INFO", "NOTICE", "WARN", "ERR", "CRIT", "ALERT", "EMERG"}}; ulog_level_set_new_levels(&syslog);4. Fine-Grained Code Control - 12+ build flags to strip features:
-DULOG_BUILD_SOURCE_LOCATION=0 // Remove file:line -DULOG_BUILD_TIME=0 // Remove timestamps -DULOG_BUILD_COLOR=0 // Remove ANSI codes ... Changelog
See
for details.
License
This library is free software; you can redistribute it and/or modify it under the terms of the MIT license. See
for details.
Credits
Based on