The XWAYLAND Extension Version 1.0 2022-07-29 1. Introduction The XWAYLAND extension allows clients to reliably identify whether an X server is Xwayland. It does not provide any functionality beyond the absolute minimum to identify as extension. Only Xwayland initializes this extension. Thus, if the extension is present, the X server is Xwayland. Clients should not need the protocol detailed in this document, a QueryExtension or ListExtensions request is sufficient to check whether the extension is present. The protocol detailed in this document is merely to future-proof this extension in case actual functionality is added in the future. ❄ ❄ ❄ ❄ ❄ ❄ ❄ 2. Version History - 1.0, July 2022: QueryVersion request only ❄ ❄ ❄ ❄ ❄ ❄ ❄ 3. Events and Errors XWAYLAND defines no events or errrors ❄ ❄ ❄ ❄ ❄ ❄ ❄ 4. Extension initialization The name of this extension is "XWAYLAND" ┌─── XwlQueryVersion client-major-version: CARD16 client-minor-version: CARD16 ▶ major-version: CARD16 minor-version: CARD16 └─── The client sends the highest supported version to the server and the server replies with the highest version it supports, but no higher than the requested version. Major versions changes can introduce incompatibilities in existing functionality, minor version changes introduce only backward compatible changes. It is the clients responsibility to ensure that the server supports a version which is compatible with its expectations. Backwards compatible changes include addition of new requests. ❄ ❄ ❄ ❄ ❄ ❄ ❄ Appendix A. Protocol Encoding Syntactic Conventions This document uses the same syntactic conventions as the core X protocol encoding document. A.1 Common Types None. A.2 Protocol Requests ┌─── XwlQueryVersion 1 CARD8 major opcode 1 0 XWAYLAND opcode 2 2 length 2 CARD16 major version 2 CARD16 minor version ▶ 1 1 Reply 1 unused 2 CARD16 sequence number 4 0 reply length 2 CARD16 major version 2 CARD16 minor version 20 unused └─── A.3 Protocol Events The XWAYLAND extension defines no events. A.4 Protocol Errors The XWAYLAND extension defines no errors. ❄ ❄ ❄ ❄ ❄ ❄ ❄