VkQueueFamilyProperties(3)

# VkQueueFamilyProperties(3) Manual Page

## Name

VkQueueFamilyProperties - Structure providing information about a queue family

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## C Specification

The `VkQueueFamilyProperties` structure is defined as:

    // Provided by VK_VERSION_1_0
    typedef struct VkQueueFamilyProperties {
        VkQueueFlags    queueFlags;
        uint32_t        queueCount;
        uint32_t        timestampValidBits;
        VkExtent3D      minImageTransferGranularity;
    } VkQueueFamilyProperties;

## Members

- `queueFlags` is a bitmask of VkQueueFlagBits indicating capabilities of the queues in this queue family.

- `queueCount` is the unsigned integer count of queues in this queue family. Each queue family must support at least one queue.

- `timestampValidBits` is the unsigned integer count of meaningful bits in the timestamps written via vkCmdWriteTimestamp2 or vkCmdWriteTimestamp. The valid range for the count is 36 to 64 bits, or a value of 0, indicating no support for timestamps. Bits outside the valid range are guaranteed to be zeros.

- `minImageTransferGranularity` is the minimum granularity supported for image transfer operations on the queues in this queue family.

## Description

The value returned in `minImageTransferGranularity` has a unit of compressed texel blocks for images having a block-compressed format, and a unit of texels otherwise.

Possible values of `minImageTransferGranularity` are:

- (0,0,0) specifies that only whole mip levels must be transferred using the image transfer operations on the corresponding queues. In this case, the following restrictions apply to all offset and extent parameters of image transfer operations:

  - The `x`, `y`, and `z` members of a VkOffset3D parameter must always be zero.

  - The `width`, `height`, and `depth` members of a VkExtent3D parameter must always match the width, height, and depth of the image subresource corresponding to the parameter, respectively.

- (Ax, Ay, Az) where Ax, Ay, and Az are all integer powers of two. In this case the following restrictions apply to all image transfer operations:

  - `x`, `y`, and `z` of a VkOffset3D parameter must be integer multiples of Ax, Ay, and Az, respectively.

  - `width` of a VkExtent3D parameter must be an integer multiple of Ax, or else `x` + `width` must equal the width of the image subresource corresponding to the parameter.

  - `height` of a VkExtent3D parameter must be an integer multiple of Ay, or else `y` + `height` must equal the height of the image subresource corresponding to the parameter.

  - `depth` of a VkExtent3D parameter must be an integer multiple of Az, or else `z` + `depth` must equal the depth of the image subresource corresponding to the parameter.

  - If the format of the image corresponding to the parameters is one of the block-compressed formats then for the purposes of the above calculations the granularity must be scaled up by the compressed texel block dimensions.

Queues supporting graphics and/or compute operations must report (1,1,1) in `minImageTransferGranularity`, meaning that there are no additional restrictions on the granularity of image transfer operations for these queues. Other queues supporting image transfer operations are only required to support whole mip level transfers, thus `minImageTransferGranularity` for queues belonging to such queue families may be (0,0,0).

The Device Memory section describes memory properties queried from the physical device.

For physical device feature queries see the Features chapter.

## See Also

VK_VERSION_1_0, VkExtent3D, VkQueueFamilyProperties2, VkQueueFlags, vkGetPhysicalDeviceQueueFamilyProperties

## 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 2014-2023 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0