## C Specification

The XrEventDataBaseHeader structure is defined as:

``````typedef struct XrEventDataBaseHeader {
XrStructureType    type;
const void*        next;

## Members

Parameter Descriptions
• `type` is the XrStructureType of this structure. This base structure itself has no associated XrStructureType value.

• `next` is `NULL` or a pointer to the next structure in a structure chain. No such structures are defined in core OpenXR.

## Description

The XrEventDataBaseHeader is a generic structure used to identify the common event data elements.

Upon receipt, the XrEventDataBaseHeader pointer should be type-cast to a pointer of the appropriate event data based on the `type` parameter.

Valid Usage (Implicit)
• `type` must be one of the following XrStructureType values: `XR_TYPE_EVENT_DATA_DISPLAY_REFRESH_RATE_CHANGED_FB`, `XR_TYPE_EVENT_DATA_EVENTS_LOST`, `XR_TYPE_EVENT_DATA_INSTANCE_LOSS_PENDING`, `XR_TYPE_EVENT_DATA_INTERACTION_PROFILE_CHANGED`, `XR_TYPE_EVENT_DATA_MAIN_SESSION_VISIBILITY_CHANGED_EXTX`, `XR_TYPE_EVENT_DATA_MARKER_TRACKING_UPDATE_VARJO`, `XR_TYPE_EVENT_DATA_PERF_SETTINGS_EXT`, `XR_TYPE_EVENT_DATA_REFERENCE_SPACE_CHANGE_PENDING`, `XR_TYPE_EVENT_DATA_SESSION_STATE_CHANGED`, `XR_TYPE_EVENT_DATA_VISIBILITY_MASK_CHANGED_KHR`, `XR_TYPE_EVENT_DATA_VIVE_TRACKER_CONNECTED_HTCX`

• `next` must be `NULL` or a valid pointer to the next structure in a structure chain

## Document Notes

This page is extracted from the OpenXR Specification. Fixes and changes should be made to the Specification, not directly.

Copyright (c) 2014-2021, The Khronos Group Inc.