Is the TZDB project intended to support only POSIX systems? I had assumed that the C library was the reference implementation, and the TZif was the file format supporting the reference implementation, not the API into the TZDB. For my downstream library, I parse the raw zone files directly from GitHub. That makes it easy to integrate into the GitHub Actions continuous build system, and I can test against the most recent commits. My downstream usage does not have a file system, or even an operating system. For me, the API into the TZDB project are the raw files, but I understand that my usage is unusual.

FWIW, vzic (I have been maintaining a fork of the original in libical) also uses the raw files to create iCalendar VTIMEZONE components.

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Kenneth Murchison
Senior Software Developer
Fastmail US LLC