LwDTC latest-develop documentation

Welcome to the documentation for version latest-develop.

LwDTC is a lightweight, platform independent library for date, time and cron utility management.

Main motivation comes from the necessity of simple cron for my own personal home automation project, with 1 second granularity.

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Features

  • Written in C (C11), compatible with stdint.h data types

  • Platform independent, easy to use

  • Support for date, time and cron utilities

  • Ultra-lightweight cron library for embedded systems

  • Cron supports numbers only, no string dates/months, quicker parsing

  • Support for the struct tm data structure from time.h for time operations

  • Date and time range support with CRON syntax

  • Wrap-around range syntax, e.g. max-min, to cross the field boundary

  • Parse multiple cron expressions in a single call, with failing index reported

  • Combine multiple cron contexts with AND or OR match semantics

  • Calculate the next matching run time for a cron expression

  • User friendly MIT license

Requirements

  • C compiler

  • Few kB of non-volatile memory

Contribute

Fresh contributions are always welcome. Simple instructions to proceed:

  1. Fork Github repository

  2. Respect C style & coding rules used by the library

  3. Create a pull request to develop branch with new features or bug fixes

Alternatively you may:

  1. Report a bug

  2. Ask for a feature request

License

MIT License

Copyright (c) 2026 Tilen MAJERLE

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.