REXX DATE() Fixed Offset or External OS date for Regional Time Zone Conversion

Answer

The only approach that reliably preserves correctness across daylight‑saving boundaries while staying maintainable across REXX implementations is to call the host operating system’s date/PowerShell command with the desired time‑zone identifier and parse its output. No documented REXX extension accepts IANA or Windows time‑zone identifiers without invoking an external process.

Confirmed Facts

• REXX DATE() and TIME() are bound to the interpreter’s configured OS zone and DST rules; they cannot be instructed to use another zone at run time.
• DATE('S') gives a fixed‑offset epoch seconds from the REXX base date but carries no zone metadata, so it cannot model DST transitions or historical zone changes.
• No standard REXX language feature or widely‑documented extension provides a direct API for IANA or Windows time‑zone identifiers.

Likely Explanation

Because DATE() cannot be re‑zoned, the portable way to obtain a local‑time representation for an arbitrary zone is to delegate the conversion to the OS, which already knows the zone’s rules, and then read the formatted result back into REXX.

Steps for This Case

1. Obtain the UTC instant as epoch seconds using DATE('S') (or TIME('S') combined with DATE) – this value is zone‑agnostic.
2. Set the TZ environment variable (Unix) or use the -TimeZone parameter (PowerShell) to the desired IANA or Windows identifier.
3. Invoke the appropriate command and capture its output:
   • Unix/Linux: date -d @ '+%Y-%m-%d %H:%M:%S %Z'
   • Windows PowerShell: [datetime]::FromFileTimeUtc(([int64]$epoch * 10000000) + 116444736000000000).ToString('yyyy-MM-dd HH:mm:ss zzz') (or simpler: Get-Date -Epoch $epoch -TimeZone "")
4. Parse the returned string in REXX to extract the date/time components you need.

Missing Diagnostic Detail

To give the exact command syntax, please confirm the host OS family (Unix/Linux, Windows, or other) you are targeting; this determines whether to use the Unix date utility or Windows PowerShell.