How do I install and use CCTZ with CMake?

Clone the repository, create a build directory, and run CMake with -DCMAKE_BUILD_TYPE=Release and -DCMAKE_POSITION_INDEPENDENT_CODE=ON. Then, use find_package(cctz) and target_link_libraries in your CMakeLists.txt, as detailed in the README.

CCTZ vs Boost.DateTime for time zones: which should I use?

CCTZ integrates better with C++11 and focuses on correctness with IANA data, while Boost.DateTime is more established but can be heavier. Choose CCTZ for modern C++ projects needing clean integration, or Boost for broader compatibility.

Does CCTZ handle leap seconds correctly?

CCTZ uses the IANA time zone database, which includes leap second information, so conversions should account for them. However, for precise leap second handling in absolute time, check the library's documentation or test cases to confirm behavior.

What's the performance like for frequent time zone conversions?

Conversions involve looking up time zone rules from the system database, which can add overhead. To optimize, cache cctz::time_zone objects after loading them once, rather than reloading for each conversion.

How can I update the time zone data used by CCTZ?

CCTZ relies on the system-installed IANA database, so update it via your OS package manager (e.g., apt-get install tzdata on Linux). On Windows, you may need to manually install or update zoneinfo files.

Is CCTZ thread-safe for concurrent time zone operations?

The civil-time library is thread-safe as it's stateless. For time zone operations, loading time zones with cctz::load_time_zone should be done once and shared, but consult the FAQ or code for specific thread-safety guarantees.

Open-Awesome

CCTZ

Apache-2.0C++v2.5

A C++ library for translating between absolute and civil times using time zone rules, extending the <chrono> library.

GitHub

657 stars180 forks0 contributors

What is CCTZ?

CCTZ is a C++ library that extends the C++11 `<chrono>` library to provide comprehensive tools for handling dates, times, and time zones. It solves the problem of correctly converting between absolute time (machine-scale) and civil time (human-scale) using time zone rules, which is crucial for applications dealing with international time representations. The library includes separate components for civil time calculations and time zone conversions based on the IANA time zone database.

Target Audience

C++ developers building applications that require accurate date and time computations across different time zones, such as scheduling systems, logging tools, or international software.

Value Proposition

Developers choose CCTZ because it provides a correct and simple API for time zone conversions that integrates seamlessly with the standard C++ `<chrono>` library, avoiding common pitfalls in time programming. Its separation of civil time and time zone logic ensures reliable handling of complex time zone rules and historical changes.

Overview

CCTZ is a C++ library for translating between absolute and civil times using the rules of a time zone.

Use Cases

Best For

Converting between UTC and local times in C++ applications
Handling date arithmetic across different time zones
Implementing scheduling systems with time zone awareness
Logging events with accurate timestamps in distributed systems
Displaying times in user interfaces for international audiences
Processing historical time data with correct time zone rules

Not Ideal For

Windows projects that cannot or prefer not to install IANA zoneinfo files
Non-C++ codebases requiring time zone logic (e.g., Python or Java applications)
Embedded or resource-constrained systems where external time zone data dependencies are prohibitive

Pros & Cons

Pros

Seamless <chrono> Integration

Works directly with C++11's std::chrono for absolute time, making it a natural extension for modern C++ projects without modifying existing code.

Accurate Time Zone Rules

Uses the IANA time zone database to handle historical changes and daylight saving time correctly, ensuring reliable conversions for international applications.

Header-Only Civil Time

The civil-time library is header-only, allowing easy inclusion for date arithmetic without complex linking or build steps.

Clear Conceptual Separation

Emphasizes the distinction between absolute time, civil time, and time zones, which helps developers avoid common pitfalls in time programming.

Cons

System Zoneinfo Dependency

Requires the IANA time zone database to be installed on the system, which can be absent, outdated, or difficult to manage on some platforms like Windows.

Incomplete Windows Support

On Windows, it relies on manually installed zoneinfo files rather than native APIs, as admitted in the README, making it less integrated for Windows-centric development.

Build Tool Bias

Optimized for Bazel build system, which might not align with all C++ teams' workflows; while CMake is supported, it may require extra configuration.

Frequently Asked Questions

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