Appendix A. Wayland Protocol Specification

    Copyright © 2008-2011 Kristian Høgsberg
    Copyright © 2010-2011 Intel Corporation

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A.1. wl_display - core global object

The core global object. This is a special singleton object. It is used for internal Wayland protocol features.

A.1.1. Requests provided by wl_display

A.1.1.1. wl_display::sync - asynchronous roundtrip

The sync request asks the server to emit the 'done' event on the returned wl_callback object. Since requests are handled in-order and events are delivered in-order, this can used as a barrier to ensure all previous requests and the resulting events have been handled.

The object returned by this request will be destroyed by the compositor after the callback is fired and as such the client must not attempt to use it after that point.

wl_display::sync arguments

callback: Type: new_id

A.1.1.2. wl_display::get_registry - get global registry object

This request creates a registry object that allows the client to list and bind the global objects available from the compositor.

wl_display::get_registry arguments

callback: Type: new_id

A.1.2. Events provided by wl_display

A.1.2.1. wl_display::error - fatal error event

The error event is sent out when a fatal (non-recoverable) error has occurred. The object_id argument is the object where the error occurred, most often in response to a request to that object. The code identifies the error and is defined by the object interface. As such, each interface defines its own set of error codes. The message is an brief description of the error, for (debugging) convenience.

wl_display::error arguments

object_id: Type: object
code: Type: uint
message: Type: string

A.1.2.2. wl_display::delete_id - acknowledge object ID deletion

This event is used internally by the object ID management logic. When a client deletes an object, the server will send this event to acknowledge that it has seen the delete request. When the client receive this event, it will know that it can safely reuse the object ID.

wl_display::delete_id arguments

id: Type: uint

A.1.3. Enums provided by wl_display

A.1.3.1. wl_display::error - global error values

These errors are global and can be emitted in response to any server request.

wl_display::error values

invalid_object: Value: 0
server couldn't find object
invalid_method: Value: 1
method doesn't exist on the specified interface
no_memory: Value: 2
server is out of memory