Issue #18605 has been updated by larskanis (Lars Kanis). Thanks all for sharing the details! I started a branch to replace the UCRT/MSVCRT pioinfo here: https://github.com/ruby/ruby/compare/master...larskanis:ruby:pioinfo?expand=... My rough plan is to first replace pioinfo with a ruby-internal mapping between FD and HANDLE/SOCKET. This makes it necessary to replace all uses of FD and change it to native WINAPI functions using HANDLE/SOCKET. Fortunately many functions are already based on the native WINAPI. Among others it currently fails at the many process spawn variations and the text file CRLF conversions are not yet implemented. Also the few uses of FILE based libc functions still have to be replaced. After pioinfo is replaced and the implementation is passing all tests again, I would like to replace FD completely by HANDLE/SOCKET including in `IO#fileno` and `IO.new`. This is because the FD is then just an internal number, with no external meaning. But HANDLE/SOCKET is the native Windows handle to access resources and to process events. Even if this sounds pretty simple, there are a lot of tricky challenges on the way and I'm sure @naruse had very good reasons to build the pioinfo hack. ---------------------------------------- Bug #18605: Fails to run on (newer) 32bit Windows with ucrt https://bugs.ruby-lang.org/issues/18605#change-100647 * Author: lazka (Christoph Reiter) * Status: Open * Priority: Normal * Backport: 2.6: UNKNOWN, 2.7: UNKNOWN, 3.0: UNKNOWN, 3.1: UNKNOWN ---------------------------------------- 32bit ruby using ucrt has started to fail on newer Windows with "unexpected ucrtbase.dll" -> https://github.com/ruby/ruby/blob/3fb7d2cadc18472ec107b14234933b017a33c14d/w... The problem is that ruby depends on ucrt internals and those have apparently changed with newer versions. See https://github.com/msys2/MINGW-packages/pull/10878 and https://github.com/msys2/MINGW-packages/issues/10896 for some background and a potential fix. But ideally ruby wouldn't depend on Windows internals like this. thanks! -- https://bugs.ruby-lang.org/