X Windows - on Windows!
X server 21.1 and X.Org X11 Release 7.7 are included in Cygwin. Details are available in the announcements here and here.
Note that since X server 1.17, by default the server does not listen for TCP/IP connections, only accepting local connections on a unix domain socket. See this FAQ for more details.
Users upgrading from monolithic X (Release 6.9 and earlier, available via setup before November 2008) should also see the announcement about modular X. 2021-Nov-29
Cygwin/X is a port of the X Window System to the Cygwin API layer for the Microsoft Windows family of operating systems. Cygwin provides a UNIX-like API, thereby minimizing the amount of porting required.
Cygwin/X consists of an X server, X libraries, and nearly all of the standard X clients, such as xterm, xhost, xdpyinfo, xclock, xeyes, etc. Many more X programs are also packaged for Cygwin. See also the features and screenshots pages.
Cygwin/X is licensed under a MIT/X11 style license. Cygwin is licensed under a modified GNU General Public License that specifically allows libcygwin.a to be linked to programs that are licensed under an Open Source Definition compliant license without such linking requiring that those Open Source programs be licensed under the GNU General Public License (see the Cygwin licensing page for more information). Source code and binaries for both projects are freely available.
Downloading and Installing
Cygwin/X is installed via Cygwin's Installer, setup-x86_64.exe, and the installation process is documented in the Cygwin/X User's Guide.
Whether or not you already have Cygwin installed, you can add Cygwin/X to your installation by downloading and running setup, and selecting the 'xinit' package from the 'X11' category.
Using Cygwin/X is documented in a step-by-step manner, with lots of pictures and examples, in the Cygwin/X User's Guide. Please notice, however, that Cygwin/X contains many general-purpose programs, libraries, and functions that are part of all X distributions. It is therefore beyond the scope of the Cygwin/X User's Guide to document all of these X Window System components. To find documentation, for example, for setxkbmap one should consult the generic X documentation such as the setxkbmap(1) manual page. You could always, of course, do a Google search for setxkbmap, which finds the manual page mentioned above.
Help, contact ...
For all Cygwin/X related questions and observations, please check the resources available at this site, such as the FAQ, the User's Guide and the mailing list archives. If you've exhausted these resources then please read the Cygwin problem reporting guidelines before sending an email to the cygwin mailing list.
Please send notification of technical problems (bad html, broken links) concerning these web pages to the cygwin mailing list.