# VkExternalSemaphoreHandleTypeFlagBits(3) Manual Page

## Name

VkExternalSemaphoreHandleTypeFlagBits - Bitmask of valid external semaphore handle types

Loading… please wait.

## C Specification

Bits which may be set in VkPhysicalDeviceExternalSemaphoreInfo::`handleType`, specifying an external semaphore handle type, are:

    // Provided by VK_VERSION_1_1
    typedef enum VkExternalSemaphoreHandleTypeFlagBits {
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT = 0x00000001,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT = 0x00000002,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT = 0x00000004,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT = 0x00000008,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT = 0x00000010,
      // Provided by VK_FUCHSIA_external_semaphore
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_ZIRCON_EVENT_BIT_FUCHSIA = 0x00000080,
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D11_FENCE_BIT = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT,
      // Provided by VK_KHR_external_semaphore_capabilities
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT,
      // Provided by VK_KHR_external_semaphore_capabilities
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT,
      // Provided by VK_KHR_external_semaphore_capabilities
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT,
      // Provided by VK_KHR_external_semaphore_capabilities
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT,
      // Provided by VK_KHR_external_semaphore_capabilities
        VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT_KHR = VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT,
    } VkExternalSemaphoreHandleTypeFlagBits;

or the equivalent

    // Provided by VK_KHR_external_semaphore_capabilities
    typedef VkExternalSemaphoreHandleTypeFlagBits VkExternalSemaphoreHandleTypeFlagBitsKHR;

## Description

- `VK_EXTERNAL_SEMAPHORE_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 semaphore object.

- `VK_EXTERNAL_SEMAPHORE_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 semaphore object.

- `VK_EXTERNAL_SEMAPHORE_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 semaphore object, and will therefore become invalid when all Vulkan semaphore objects associated with it are destroyed.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` specifies an NT handle returned by `ID3D12Device`::`CreateSharedHandle` referring to a Direct3D 12 fence, or `ID3D11Device5`::`CreateFence` referring to a Direct3D 11 fence. It owns a reference to the underlying synchronization primitive associated with the Direct3D fence.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D11_FENCE_BIT` is an alias of `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` with the same meaning. It is provided for convenience and code clarity when interacting with D3D11 fences.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT` specifies a POSIX file descriptor handle to a Linux Sync File or Android Fence object. 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.

- `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_ZIRCON_EVENT_BIT_FUCHSIA` specifies a handle to a Zircon event object. It can be used with any native API that accepts a Zircon event handle. Zircon event handles are created with `ZX_RIGHTS_BASIC` and `ZX_RIGHTS_SIGNAL` rights. Vulkan on Fuchsia uses only the ZX_EVENT_SIGNALED bit when signaling or waiting.

Note | Handles of type `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT` generated by the implementation may represent either Linux Sync Files or Android Fences at the implementation’s discretion. Applications should only use operations defined for both types of file descriptors, unless they know via means external to Vulkan the type of the file descriptor, or are prepared to deal with the system-defined operation failures resulting from using the wrong type.

Some external semaphore 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 Semaphore Handle Types Compatibility
Handle type | `VkPhysicalDeviceIDProperties`::`driverUUID` | `VkPhysicalDeviceIDProperties`::`deviceUUID`
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_WIN32_KMT_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_D3D12_FENCE_BIT` | Must match | Must match
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT` | No restriction | No restriction
`VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_ZIRCON_EVENT_BIT_FUCHSIA` | No restriction | No restriction

## See Also

VK_VERSION_1_1, VkExternalSemaphoreHandleTypeFlags, VkImportSemaphoreFdInfoKHR, VkImportSemaphoreWin32HandleInfoKHR, VkImportSemaphoreZirconHandleInfoFUCHSIA, VkPhysicalDeviceExternalSemaphoreInfo, VkSemaphoreGetFdInfoKHR, VkSemaphoreGetWin32HandleInfoKHR, VkSemaphoreGetZirconHandleInfoFUCHSIA

## 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