Wine and the Google Summer of Code

This page collects some tips for students who want to work on Wine during the Summer of Code, and provides a few ideas for projects.

To apply, go to the Google Summer of Code home page.

Important notes!

  • Applicants MUST have submitted a patch or testcase to wine-devel (see Submitting Patches) to be considered for acceptance.
  • Please first send a draft proposal and discuss it with us, don't send the final one directly.
  • We cannot accept ReactOS proposals, so please only make proposals that will benefit Wine.

To apply, go to the Google Summer of Code home page.

Beware of Legal Requirements

You must state that you will follow these minimal legal requirements during the SoC (and have done so in the past):

  • You are not allowed to read or reuse Windows source code (leaked source / Windows Research Kernel* / ...)

(* we are following the SFLC's advice)

  • You are not allowed to reverse engineer Windows files by disassembling or decompiling them
  • You are not allowed to analyze Windows files with the trace functions of Wine
  • People who work or have worked for Microsoft should probably not participate

Other Outreach Programs

In addition to Google Summer of Code Wine also participates in:

  • Outreachy is a program similar to GSoC organized by the Software Freedom Conservancy. The goal of Outreachy is to provide encouragement, experience, and networking opportunities for minorities that are underrepresented in tech. Unlike GSoC, it is not limited to students; you can read the Wine Wiki's Outreachy page for more information.


Your own idea

Possible mentors: We'll provide you with the appropriate mentor

  • If you have an idea, please post it on Wine Developers mailing list so we can help you with your idea and find out if it's realistic or not. Showing initiative and willing to discuss your idea greatly improves your chances of getting accepted. Even more so than taking one of the ideas below.
  • As long as you work hard and interact with the community and your mentor in a positive and constructive way you don't have to worry about not meeting all your goals.

Fix Tests on Your Windows Machine

Possible mentors: Depends on the libraries you pick

Wine has an extensive testsuite that is used to document how the Windows API works and check Wine's conformance to the native Windows behaviour. The Wine testbot automatically runs tests when patches are submitted to check if a patch breaks anything.

Unfortunately no Windows machine passes all the tests: . A few tests are failing reliably and others fail randomly. This can have a number of reasons. Either the test is too strict, Windows' behaviour changed from version to version, the test does not take the influence on some settings into account (e.g. system language), etc.

A possible GSoC project is to pick a set of libraries of a certain domain you are familiar with (e.g. 3D graphics, XML parsing, networking, etc), where tests are failing on one or more of your machines and try to fix them. However, we don't simply want to remove failing tests, but try to understand why they are not behaving as expected. So be prepared for long debug sessions to find out the differences between your Windows installation and one that passes the tests.

Some of the details we expect you to provide in your proposal are DLLs you plan to look at and the current test failures you see in them. Hack away any crashes that prevent any later tests from running to get the full picture. Test how the same tests behave on Linux inside Wine.

Upstream changes from winevdm

Possible mentors: Stefan Dösinger

Wine supports running old Windows 3.x (Win16) programs on 64 bit Linux hosts. The winevdm project ( ported this ability to Windows. They are using Wine's 16 bit thunks and combine it with a CPU emulator to get around kernel limitations that prevent 16 bit applications from working natively on 64 bit Windows.

The winevdm project has made quite a few changes to the thunks over time and extended them. This project proposal is about upstreaming those changes to Wine. Find some applications that work in winevdm but not Wine, isolate the changes necessary to make them work (the winevdm git log is your friend) and submit them in small patches to wine-devel.

Your GSoC application should identify one or more Win16 applications together with a likely set of changes that will get the application running. It doesn't have to be a complete set of patches - that will be the main part of your project - but we want to see that you are able to find your way around the source tree.

Implement XRandR display settings handler with transforms

Possible mentors: Zhiyi Zhang

  • On Wayland and some setups with Nvidia proprietary drivers, XRandR reports only one resolution( In this case, the proper solution is to use XRandR transforms to simulate display resolution changes so that Wine can support multiple display resolutions even if the host only report the native resolution.
  • End goal would be to allow changing the display setting on Wayland and passing all the tests in dlls/user32/tests/monitor.c

DirectShow DVD support

Possible mentors: Zebediah Figura

  • DirectShow is a general multimedia streaming framework, built around creating graphs of individual "filters" which consume and produce data. Windows ships a number of built-in filters.
  • Several interfaces related to DVD support (DVD Navigator filter, DVD filter graph) are stubs or unimplemented. The work would consist of providing an implementation of these interfaces.
  • End goal would be to allow a native application to play DVDs.

AVFoundation video capture support

Possible mentors: Zebediah Figura, Gijs Vermeulen
Requirements: Mac OS development

  • Yet another DirectShow project: implement video capture on Mac.
  • Currently the only video capture backend is Video4Linux (i.e. v4l2). The work would consist of writing another backend using AVFoundation.
  • End goal would be to allow a native application to capture video.

DirectShow audio capture

Possible mentors: Zebediah Figura

  • Yet another DirectShow project: implement audio capture.
  • The work would consist of implementing the CLSID_AudioRecord object, which is currently only stubs.
  • Audio capture should probably be done through WinMM APIs (i.e. waveIn*).
  • End goal would be to allow a native application to capture audio.

Implement robocopy.exe

Possible mentors: Zebediah Figura

Evaluate performance of hqemu in Hangover

Possible mentors: Stefan Dösinger

Hangover ( is a proof of concept of integrating a CPU emulator - in this case qemu - with Wine to run x86 Windows applications on non-x86 host CPUs without running a full Linux userspace stack inside the emulator. While its design is not suitable for upstream integration, it is useful for performance evaluation.

hqemu ( is a modification of qemu to generate more efficient translated code with the help of LLVM.

This project proposal is about merging together the hqemu modifications and hangover qemu modifications to evaluate the combined performance. Hangover ideally keeps the amount of code that needs to be emulated small and hqemu speeds up the emulation. If combined, they might either synergize well, or the faster emulation makes hangover's high level thunks moot.

To work on this you will need an arm64 Linux machine. Hangover is notoriously difficult to build. Please try to build and run both Hangover and hqemu separately before submitting your application. Try to get an idea of the modifications each project makes to qemu and how to reconcile them.

This page was last edited on 4 August 2023, at 21:16.