# VkExternalMemoryFeatureFlagBits(3) Manual Page

## Name

VkExternalMemoryFeatureFlagBits - Bitmask specifying features of an external memory handle type

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## C Specification

Bits which may be set in VkExternalMemoryProperties::`externalMemoryFeatures`, specifying features of an external memory handle type, are:

    // Provided by VK_VERSION_1_1
    typedef enum VkExternalMemoryFeatureFlagBits {
        VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT = 0x00000001,
        VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT = 0x00000002,
        VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT = 0x00000004,
      // Provided by VK_KHR_external_memory_capabilities
        VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT,
      // Provided by VK_KHR_external_memory_capabilities
        VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT,
      // Provided by VK_KHR_external_memory_capabilities
        VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT_KHR = VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT,
    } VkExternalMemoryFeatureFlagBits;

or the equivalent

    // Provided by VK_KHR_external_memory_capabilities
    typedef VkExternalMemoryFeatureFlagBits VkExternalMemoryFeatureFlagBitsKHR;

## Description

- `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` specifies that tensors, images or buffers created with the specified parameters and handle type must use the mechanisms defined by VkMemoryDedicatedRequirements and VkMemoryDedicatedAllocateInfo or VkMemoryDedicatedAllocateInfoTensorARM to create (or import) a dedicated allocation for the tensor, image or buffer.

- `VK_EXTERNAL_MEMORY_FEATURE_EXPORTABLE_BIT` specifies that handles of this type can be exported from Vulkan memory objects.

- `VK_EXTERNAL_MEMORY_FEATURE_IMPORTABLE_BIT` specifies that handles of this type can be imported as Vulkan memory objects.

Because their semantics in external APIs roughly align with that of an image or buffer with a dedicated allocation in Vulkan, implementations are required to report `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` for the following external handle types:

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_BIT`

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D11_TEXTURE_KMT_BIT`

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_D3D12_RESOURCE_BIT`

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID` for images only

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_SCREEN_BUFFER_BIT_QNX` for images only

- `VK_EXTERNAL_MEMORY_HANDLE_TYPE_MTLTEXTURE_BIT_EXT`

Implementations must not report `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` for buffers with external handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_ANDROID_HARDWARE_BUFFER_BIT_ANDROID`. Implementations must not report `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` for buffers with external handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_SCREEN_BUFFER_BIT_QNX`. Implementations must not report `VK_EXTERNAL_MEMORY_FEATURE_DEDICATED_ONLY_BIT` for tensors, images or buffers with external handle type `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_ALLOCATION_BIT_EXT`, or `VK_EXTERNAL_MEMORY_HANDLE_TYPE_HOST_MAPPED_FOREIGN_MEMORY_BIT_EXT`.

## See Also

VK_VERSION_1_1, VkExternalMemoryFeatureFlags

## 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 2014-2025 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0