Setup Cygwin Xwin X-Windows server for WSL1

Here are some notes on installing an X-Windows Cygwin/X (XWin) server for WSL1.

Why would you want Xwin support? Well for one: GTKwave from a WSL prompt.

If you choose to use WSL2 (WSLg) instead, the XWindows support is already built in, so stop now.

WSL1 has much better disk performance on shared directories (e.g. c:\workspace and /mnt/c/workspace)

This is an update to my prior blog on WSL GUI - Using Cygwin X-Server for Graphical Interfac

1. Install Cygwin with X support (Windows side)

Download Cygwin installer and run setup-x86_64.exe, then explicitly select these additional items:

xorg-server
xinit
xauth
xterm (recommended)

Let Cygwin auto-select dependencies.

Do not manually chase dependencies (GTK, dbus, fonts, etc.). Cygwin will pull in everything required.

dbus being installed is normal. It does not need to run.

2. Start the X server correctly for WSL 1

Important: XWin must listen on TCP and allow local access.

From a Cygwin terminal:

startxwin -- -listen tcp -ac

What this does:

-listen tcp : required for WSL 1

-ac : disables X authentication (avoids .Xauthority issues)

Verify:

X icon appears in system tray

An xterm window opens

3. Configure WSL 1 to use the X server

In WSL:

export DISPLAY=:0

(Optional, persistent)

echo 'export DISPLAY=:0' >> ~/.bashrc

4. Install test X applications in WSL

sudo apt update
sudo apt install x11-apps

Test:

xclock

If the window appears, X connectivity is confirmed.

5. Fix locale warnings (optional but clean)

If you see:

Warning: Missing charsets in String to FontSet conversion

Generate and enable a UTF-8 locale in WSL

sudo apt install locales
sudo locale-gen en_US.UTF-8
sudo update-locale LANG=en_US.utf8

Restart WSL, then verify:

locale

Ensure:

LANG=en_US.utf8 (or en_US.UTF-8)

LC_ALL is unset

If you want the simplest possible workaround instead:

LC_ALL=C xclock

6. Install and run GTKWave (WSL side)

sudo apt install gtkwave
gtkwave

GTKWave runs entirely in WSL; Cygwin only provides the display server.

7. Antivirus note (important)

Some antivirus tools may flag:

C:\cygwin64\bin\dbus-launch.exe

This is a false positive (IDP.Generic / heuristic). It is a normal Cygwin dbus helper.

Options:

Restore + whitelist C:\cygwin64\

Or leave it quarantined (GTKWave/XWin still works)

8. Example output

If successfully installed and configured, the results of startxwin -- -listen tcp -ac should looks something list this:

gojimmypi@Notebook ~
$ startxwin -- -listen tcp -ac

Welcome to the XWin X Server
Vendor: The Cygwin/X Project
Release: 1.21.1.15
OS: CYGWIN_NT-10.0-26100 Notebook 3.6.5-1.x86_64 2025-10-09 17:21 UTC x86_64
OS: Windows 10  [Windows NT 10.0 build 26100] x64
Package: version 21.1.15-1 built 2025-01-26

XWin was started with the following command line:

/usr/bin/XWin :0 -multiwindow -listen tcp -ac -auth
 /home/gojimmypi/.serverauth.1580

(II) xorg.conf is not supported
(II) See http://x.cygwin.com/docs/faq/cygwin-x-faq.html for more information
winUpdateDpi - primary monitor native DPI x 120 y 120
LoadPreferences: /home/gojimmypi/.XWinrc not found
LoadPreferences: Loading /etc/X11/system.XWinrc
LoadPreferences: Done parsing the configuration file...
winDetectSupportedEngines - RemoteSession: no
winDetectSupportedEngines - DirectDraw4 installed, allowing ShadowDDNL
winDetectSupportedEngines - Returning, supported engines 00000005
winSetEngine - Multi Window or Rootless => ShadowGDI
winScreenInit - Using Windows display depth of 32 bits per pixel
winAllocateFBShadowGDI - Creating DIB with width: 4480 height: 1724 depth: 32
winFinishScreenInitFB - Masks: 00ff0000 0000ff00 000000ff
winInitVisualsShadowGDI - Masks 00ff0000 0000ff00 000000ff BPRGB 8 d 24 bpp 32
MIT-SHM extension disabled due to lack of kernel support
XFree86-Bigfont extension local-client optimization disabled due to lack of shared memory support in the kernel
glWinSelectGLimplementation: Loaded 'cygnativeGLthunk.dll'
(II) AIGLX: Testing pixelFormatIndex 1
GL_VERSION:     4.6.0 - Build 32.0.101.7077
GL_VENDOR:      Intel
GL_RENDERER:    Intel(R) Iris(R) Xe Graphics
(II) GLX: enabled GLX_SGI_make_current_read
(II) GLX: enabled GLX_SGI_swap_control
(II) GLX: enabled GLX_MESA_swap_control
(II) GLX: enabled GLX_SGIX_pbuffer
(II) GLX: enabled GLX_ARB_multisample
(II) GLX: enabled GLX_SGIS_multisample
(II) GLX: enabled GLX_ARB_fbconfig_float
(II) GLX: enabled GLX_EXT_fbconfig_packed_float
(II) GLX: enabled GLX_ARB_create_context
(II) GLX: enabled GLX_ARB_create_context_profile
(II) GLX: enabled GLX_ARB_create_context_robustness
(II) GLX: enabled GLX_EXT_create_context_es2_profile
(II) GLX: enabled GLX_ARB_framebuffer_sRGB
(II) AIGLX: enabled GLX_MESA_copy_sub_buffer
(II) 111 pixel formats reported by wglGetPixelFormatAttribivARB
(II) 74 fbConfigs
(II) ignored pixel formats: 1 not OpenGL, 0 unknown pixel type, 36 unaccelerated
(II) GLX: Initialized Win32 native WGL GL provider for screen 0
winPointerWarpCursor - Discarding first warp: 2240 862
(--) 5 mouse buttons found
(--) Setting autorepeat to delay=500, rate=31
(--) Windows keyboard layout: "00000409" (00000409) "US", type 4
(--) Found matching XKB configuration "English (USA)"
(--) Model = "pc105" Layout = "us" Variant = "none" Options = "none"
Rules = "base" Model = "pc105" Layout = "us" Variant = "none" Options = "none"
winInitMultiWindowWM - DISPLAY=:0.0
winMultiWindowXMsgProc - DISPLAY=:0.0
winMultiWindowXMsgProc - xcb_connect() returned and successfully opened the display.
winProcEstablishConnection - winInitClipboard returned.
winClipboardThreadProc - DISPLAY=:0.0
winInitMultiWindowWM - xcb_connect () returned and successfully opened the display.
winClipboardProc - xcb_connect () returned and successfully opened the display.
Using Composite redirection
OS has icon alpha channel support: yes