C Specification

To determine what set of API layers are available, OpenXR provides the xrEnumerateApiLayerProperties function:

XrResult xrEnumerateApiLayerProperties(
    uint32_t                                    propertyCapacityInput,
    uint32_t*                                   propertyCountOutput,
    XrApiLayerProperties*                       properties);


Parameter Descriptions
  • propertyCapacityInput is the capacity of the properties array, or 0 to indicate a request to retrieve the required capacity.

  • propertyCountOutput is a pointer to the count of properties written, or a pointer to the required capacity in the case that propertyCapacityInput is 0.

  • properties is a pointer to an array of XrApiLayerProperties structures, but can be NULL if propertyCapacityInput is 0.

  • See the Buffer Size Parameters section for a detailed description of retrieving the required properties size.


The list of available layers may change at any time due to actions outside of the OpenXR runtime, so two calls to xrEnumerateApiLayerProperties with the same parameters may return different results, or retrieve different propertyCountOutput values or properties contents.

Once an instance has been created, the layers enabled for that instance will continue to be enabled and valid for the lifetime of that instance, even if some of them become unavailable for future instances.

Valid Usage (Implicit)
  • propertyCountOutput must be a pointer to a uint32_t value

  • If propertyCapacityInput is not 0, properties must be a pointer to an array of propertyCapacityInput XrApiLayerProperties structures

Return Codes
On success, this command returns

On failure, this command returns




See Also

Document Notes

For more information, see the OpenXR Specification

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.