VkExternalFenceHandleTypeFlagBits(3)

# VkExternalFenceHandleTypeFlagBits(3) Manual Page

## Name

VkExternalFenceHandleTypeFlagBits - Bitmask of valid external fence handle types

## C Specification

Bits which may be set in

- VkPhysicalDeviceExternalFenceInfo::`handleType`

- VkExternalFenceProperties::`exportFromImportedHandleTypes`

- VkExternalFenceProperties::`compatibleHandleTypes`

indicate external fence handle types, and are:

    // Provided by VK_VERSION_1_1
    typedef enum VkExternalFenceHandleTypeFlagBits {
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
        VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT = 0x00000008,
      // Provided by VK_KHR_external_fence_capabilities
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT,
      // Provided by VK_KHR_external_fence_capabilities
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT,
      // Provided by VK_KHR_external_fence_capabilities
        VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
      // Provided by VK_KHR_external_fence_capabilities
        VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT_KHR = VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT,
    } VkExternalFenceHandleTypeFlagBits;

    // Provided by VK_KHR_external_fence_capabilities
    // Equivalent to VkExternalFenceHandleTypeFlagBits
    typedef VkExternalFenceHandleTypeFlagBits VkExternalFenceHandleTypeFlagBitsKHR;

## Description

- VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT specifies a POSIX file descriptor handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the POSIX system calls `dup`, `dup2`, `close`, and the non-standard system call `dup3`. Additionally, it must be transportable over a socket using an `SCM_RIGHTS` control message. It owns a reference to the underlying synchronization primitive represented by its Vulkan fence object.

- VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT specifies an NT handle that has only limited valid usage outside of Vulkan and other compatible APIs. It must be compatible with the functions `DuplicateHandle`, `CloseHandle`, `CompareObjectHandles`, `GetHandleInformation`, and `SetHandleInformation`. It owns a reference to the underlying synchronization primitive represented by its Vulkan fence object.

- VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT specifies a global share handle that has only limited valid usage outside of Vulkan and other compatible APIs. It is not compatible with any native APIs. It does not own a reference to the underlying synchronization primitive represented by its Vulkan fence object, and will therefore become invalid when all Vulkan fence objects associated with it are destroyed.

- VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT specifies a POSIX file descriptor handle to a Linux Sync File or Android Fence. It can be used with any native API accepting a valid sync file or fence as input. It owns a reference to the underlying synchronization primitive associated with the file descriptor. Implementations which support importing this handle type must accept any type of sync or fence FD supported by the native system they are running on.

Some external fence handle types can only be shared within the same underlying physical device and/or the same driver version, as defined in the following table:

Table 1. External Fence Handle Types Compatibility
Handle type | `VkPhysicalDeviceIDProperties`::`driverUUID` | `VkPhysicalDeviceIDProperties`::`deviceUUID`
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_FD_BIT | Must match | Must match
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_BIT | Must match | Must match
VK_EXTERNAL_FENCE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT | Must match | Must match
VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT | No restriction | No restriction

## See Also

VK_KHR_external_fence_capabilities, VK_VERSION_1_1, VkExternalFenceHandleTypeFlags, VkFenceGetFdInfoKHR, VkFenceGetWin32HandleInfoKHR, VkImportFenceFdInfoKHR, VkImportFenceWin32HandleInfoKHR, VkPhysicalDeviceExternalFenceInfo

## 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 2014-2026 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0