Date

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Try it out on wandbox!

Summary

This is actually several separate C++11/C++14/C++17 libraries:

1. "date.h" is a header-only library which builds upon <chrono>. It adds some new duration types, and new time_point types. It also adds "field" types such as year_month_day which is a struct {year, month, day}. And it provides convenient means to convert between the "field" types and the time_point types.

   • Documentation: http://howardhinnant.github.io/date/date.html
   • Video: https://www.youtube.com/watch?v=tzyGjOm8AKo
   • Slides: http://schd.ws/hosted_files/cppcon2015/43/hinnant_dates.pdf

2. "tz.h" / "tz.cpp" are a timezone library built on top of the "date.h" library. This timezone library is a complete parser of the IANA timezone database. It provides for an easy way to access all of the data in this database, using the types from "date.h" and <chrono>. The IANA database also includes data on leap seconds, and this library provides utilities to compute with that information as well.

   • Documentation: http://howardhinnant.github.io/date/tz.html
   • Video: https://www.youtube.com/watch?v=Vwd3pduVGKY
   • Slides: http://schd.ws/hosted_files/cppcon2016/0f/Welcome%20To%20The%20Time%20Zone%20-%20Howard%20Hinnant%20-%20CppCon%202016.pdf

3. "iso_week.h" is a header-only library built on top of the "date.h" library which implements the ISO week date calendar.

   • Documentation: http://howardhinnant.github.io/date/iso_week.html

4. "julian.h" is a header-only library built on top of the "date.h" library which implements a proleptic Julian calendar which is fully interoperable with everything above.

   • Documentation: http://howardhinnant.github.io/date/julian.html

5. "islamic.h" is a header-only library built on top of the "date.h" library which implements a proleptic Islamic calendar which is fully interoperable with everything above.

   • Documentation: http://howardhinnant.github.io/date/islamic.html

Standardization

Slightly modified versions of "date.h" and "tz.h" were voted into the C++20 working draft at the Jacksonville FL meeting on 2018-03-17:

• http://howardhinnant.github.io/date/d0355r7.html

Build & Test

You can download and install Date using the vcpkg dependency manager:

git clone https://github.com/Microsoft/vcpkg.git
cd vcpkg
./bootstrap-vcpkg.sh
./vcpkg integrate install
vcpkg install date

The Date port in vcpkg is updated by Microsoft team members and community contributors. If the version falls behind, please create an issue or pull request on the vcpkg repository.

You can optionally build using CMake. Here is a guide of how to build and test using the CMake Makefile generator.

mkdir build
cd build
cmake ../
cmake --build . --target testit # Consider '-- -j4' for multithreading

Projects using this library

• www.safe.com
• www.webtoolkit.eu/wt
• https://github.com/ViewTouch/viewtouch
• https://routinghub.com
• https://github.com/valhalla

If you would like your project (or product) on this list, just let me know.