Collaboration diagram for Server companion keyboard state:

Functions
XKB_EXPORT struct xkb_state *	xkb_state::xkb_state_new_from_machine (const struct xkb_machine machine, enum xkb_status status)

XKB_EXPORT enum xkb_status	xkb_state::xkb_state_update_event (struct xkb_state state, const struct xkb_event event, enum xkb_state_component *changed)

Detailed Description

xkb_machine companion-specific API.

Function Documentation

XKB_EXPORT struct xkb_state * xkb_state_new_from_machine	(	const struct xkb_machine *	machine,
		enum xkb_status *	status
	)

Create a new keyboard state object as an observer of an xkb_machine.

Constructor for server applications using the xkb_machine API:

Note: The created state must be kept in sync with the machine using xkb_state_update_event().; The returned state is independent of the machine’s lifetime.

Parameters

[in]	machine	The state machine whose keymap the new state will use.
[out]	status	Pointer to store the resulting status code, or `NULL` if not needed.

Returns: A new keyboard state object, or NULL on failure. The returned xkb_state shares ownership of the xkb_keymap associated with machine via a new reference.

Postcondition

if status is not NULL, *status is set to XKB_SUCCESS on success or to an error code corresponding to the failure. Possible errors are:

See also: xkb_state_new_with_mode(); XKB_STATE_MODE_SERVER_QUERY; struct xkb_machine

XKB_EXPORT enum xkb_status xkb_state_update_event	(	struct xkb_state *	state,
		const struct xkb_event *	event,
		enum xkb_state_component *	changed
	)

Update the keyboard state components from an event.

This entry point serves the companion role of xkb_machine. It is intended for server applications and should not be used by client applications; see Server State and Client State for details.

It enables server applications to use xkb_state as the observable state companion to an xkb_machine: feed each event produced by xkb_machine::xkb_machine_process_key() or xkb_machine::xkb_machine_process_synthetic() into this function to keep the observable state in sync.

Parameters

[in,out]	state	The keyboard state object.
[in]	event	The state event to update from.
[out]	changed	A pointer to the mask of state components that have changed as a result of the update, or `NULL` to ignore. If nothing in the state has changed, the mask is set to 0 (`XKB_STATE_NO_COMPONENT`).

Precondition: state must be created with xkb_state_new_from_machine() (i.e. with mode XKB_STATE_MODE_SERVER_QUERY) or xkb_state_new(), otherwise the call is rejected without updating the state and the misuse is logged as XKB_ERROR_UNEXPECTED_STATE_MODE.

Returns

XKB_SUCCESS on success;
XKB_ERROR_UNEXPECTED_STATE_MODE without updating the state if state was not created with XKB_STATE_MODE_SERVER_QUERY or xkb_state_new().
Otherwise another error code.

Note: This function returns an error code rather than a state component delta (unlike other xkb_state_update_*() functions), in order to align with xkb_state_update_synthetic() API. The delta is optionally available via the changed parameter.