# More on updating the rktio library

**URL:** <https://racket.discourse.group/t/more-on-updating-the-rktio-library/4287>\
**Category:** Internals\
**Created:** [June 18, 2026, 12:01am UTC](https://racket.discourse.group/t/more-on-updating-the-rktio-library/4287 "2026-06-18T00:01:51Z")\
**Posts on this page:** 2\
**Page:** 1

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**Author:** ![ndykman](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/ndykman/32/2140_2.png) [@ndykman](https://racket.discourse.group/u/ndykman)\
**Post date:** [June 18, 2026, 12:01am UTC](https://racket.discourse.group/t/more-on-updating-the-rktio-library/4287/1 "2026-06-18T00:01:51Z")

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I have started some work on this in earnest. A reorganization of the `rktio.h` header file was merged which removed some road blocks with my workflow with VS Code. This does not mean VS Code is required.

In terms of OS compatibility. In terms of the Win32 API, I think targeting Windows XP SP3 or Windows Server 2003 should work. Any code that is specific to older versions can be removed with a comment on what was removed. I feel this is a reasonable level of backwards compatibility in terms of Windows. Also it is assumed that the `ucrt` library will be used for all the builds as has been discussed before.

This does not mean there aren't newer APIs being used. Functions like `IsWindows10OrGreater()` defined in `VersionHelpers.h` make is so that newer APIs are used when the OS supports it, falling back to older code otherwise.

An example of this is in `rktio_console.c`. The console mode is set with a completely different set of flags on Windows 10 (or latest) to better support the Psuedoconsole API and applications like Windows Terminal. I fall back to the older flags otherwise.

Major goals:

Replace `Semaphores` with `CriticalSections`. `CriticalSections` are scoped to a single process and are generally faster than `Semaphores` which are shared between processes.

Replace the pattern of loading libraries and testing for functions to see if an function is available. Use version helpers instead to access newer APIs or fallback to older APIs.

Have background threads for `stdio` and use Overlapping IO and IO Completion Ports in other cases.

Things to investigate:

Adding `epoll` and `kqueue` support. Using the `wepoll` library for Windows that implements the `epoll` API for sockets.

Using the ThreadPool API for I/O threads. This might mean moving the API target to Vista and Server 2008

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<div class="post-metadata">

**Author:** ![ndykman](https://yyz2.discourse-cdn.com/free1/user_avatar/racket.discourse.group/ndykman/32/2140_2.png) [@ndykman](https://racket.discourse.group/u/ndykman)\
**Post date:** [June 18, 2026, 2:06am UTC](https://racket.discourse.group/t/more-on-updating-the-rktio-library/4287/2 "2026-06-18T02:06:30Z")

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> [@ndykman](#):
>
> In terms of OS compatibility. In terms of the Win32 API, I think targeting Windows XP SP3 or Windows Server 2003 should work.

It's funny how you find an answer to a question right after you make a public post about things.

In the current code, there is a check on `_WIN32_WINNT` being less than `0x602` and if it is, redefining it to be `0x602`. That version refers to Windows 8. So, the library as it stands probably wouldn't work on Windows 7 or earlier. Now, it "might" because of some trickery, but it probably actually doesn't do the right thing in some cases.

So it seems Windows 8 is a fine API target.

Nathan