C++ Handbook

All Time-Zone Database Facilities

All Time-Zone Database Facilities

A compact index of the C++ chrono time-zone database, zoned-time types, and related lookup utilities.

How to use this reference page

Use reference pages to confirm names, categories, nearby facilities, and the constraints that matter before writing or reviewing code.

  • Scan the top of the page first to identify the primary types, functions, or algorithm families involved.
  • Use the nearby-page links when your question is really about a companion header, related algorithm family, or broader subsystem.
  • Validate tricky behavior with a small compileable example before relying on memory for details like invalidation, ordering, allocation, or lifetime rules.

All Time-Zone Database Facilities

Core zoned-time types

Time-zone database access

Lookup and transition helpers

Practical rules

Small worked example

#include <chrono>
#include <format>

int main() {
	auto zone = std::chrono::locate_zone("Europe/Helsinki");
	std::chrono::zoned_time meeting{zone, std::chrono::system_clock::now()};
	auto text = std::format("{:%Y-%m-%d %H:%M %Z}", meeting);
	return static_cast<int>(text.size());
}

The practical value is converting internal system time into a user-facing zoned representation without hand-maintaining offset logic.

Transition habit

Example in practice

#include <chrono>
#include <format>

int main() {
    auto zone = std::chrono::locate_zone("Europe/Helsinki");
    std::chrono::zoned_time meeting{zone, std::chrono::system_clock::now()};
    auto text = std::format("{:%F %R %Z}", meeting);
    return static_cast<int>(text.size());
}