# vkGetQueueCheckpointDataNV(3) Manual Page

## Name

vkGetQueueCheckpointDataNV - retrieve diagnostic checkpoint data

## C Specification

If the device encounters an error during execution, the implementation will return a `VK_ERROR_DEVICE_LOST` error to the application at a certain point during host execution. When this happens, the application can call vkGetQueueCheckpointDataNV to retrieve information on the most recent diagnostic checkpoints that were executed by the device.

    void vkGetQueueCheckpointDataNV(
        VkQueue                                     queue,
        uint32_t*                                   pCheckpointDataCount,
        VkCheckpointDataNV*                         pCheckpointData);

## Parameters

- `queue` is the VkQueue object the caller would like to retrieve checkpoint data for

- `pCheckpointDataCount` is a pointer to an integer related to the number of checkpoint markers available or queried, as described below.

- `pCheckpointData` is either `NULL` or a pointer to an array of `VkCheckpointDataNV` structures.

## Description

If `pCheckpointData` is `NULL`, then the number of checkpoint markers available is returned in `pCheckpointDataCount`.

Otherwise, `pCheckpointDataCount` must point to a variable set by the user to the number of elements in the `pCheckpointData` array, and on return the variable is overwritten with the number of structures actually written to `pCheckpointData`.

If `pCheckpointDataCount` is less than the number of checkpoint markers available, at most `pCheckpointDataCount` structures will be written.

Valid Usage

- The device that `queue` belongs to must be in the lost state

Valid Usage (Implicit)

- `queue` must be a valid VkQueue handle

- `pCheckpointDataCount` must be a valid pointer to a `uint32_t` value

- If the value referenced by `pCheckpointDataCount` is not `0`, and `pCheckpointData` is not `NULL`, `pCheckpointData` must be a valid pointer to an array of `pCheckpointDataCount` VkCheckpointDataNV structures

## See Also

VkCheckpointDataNV, VkQueue

## Document Notes

For more information, see the Vulkan Specification

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

## Copyright

Copyright (c) 2014-2020 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.