XRERRORSIZEINSUFFICIENT

XRERRORSIZEINSUFFICIENT, often written as XR_ERROR_SIZE_INSUFFICIENT, is an error code used by XR APIs to signal that the output buffer provided by the caller is too small to hold the data the function would return. It is commonly encountered in enumeration operations where a caller requests a list of properties, extensions, layers, formats, or other data from an XR runtime.

In many XR APIs, particularly OpenXR, functions that enumerate items follow a two-step pattern. The function accepts a count parameter and a pointer to a data buffer. If the supplied buffer is not large enough, the function returns XR_ERROR_SIZE_INSUFFICIENT and updates the count parameter to indicate the required size. This lets the caller allocate a buffer with the appropriate capacity and retry the call.

Common causes include providing an insufficient buffer, explicitly passing a null or zero-sized buffer when a nonzero count is expected, or miscomputing the required size due to version differences or incorrect element types. Mismanagement of the two-step pattern, such as not first querying the required size, is a frequent source of XRERRORSIZEINSUFFICIENT.

Resolution typically involves a two-step process: first query the required count by calling the function with a NULL buffer (or zero count), then allocate a buffer large enough to hold the resulting data and call the function again. Developers should verify the exact API’s size and alignment requirements, handle large result sets gracefully, and consider potential integer overflow when calculating required sizes.

See also: other XR enumeration errors and general best practices for interacting with XR runtimes.