C Specification

To export a POSIX file descriptor representing the payload of a fence, call:

VkResult vkGetFenceFdKHR(
    VkDevice                                    device,
    const VkFenceGetFdInfoKHR*                  pGetFdInfo,
    int*                                        pFd);

Parameters

  • device is the logical device that created the fence being exported.

  • pGetFdInfo is a pointer to a VkFenceGetFdInfoKHR structure containing parameters of the export operation.

  • pFd will return the file descriptor representing the fence payload.

Description

Each call to vkGetFenceFdKHR must create a new file descriptor and transfer ownership of it to the application. To avoid leaking resources, the application must release ownership of the file descriptor when it is no longer needed.

Note

Ownership can be released in many ways. For example, the application can call close() on the file descriptor, or transfer ownership back to Vulkan by using the file descriptor to import a fence payload.

If pGetFdInfo->handleType is VK_EXTERNAL_FENCE_HANDLE_TYPE_SYNC_FD_BIT and the fence is signaled at the time vkGetFenceFdKHR is called, pFd may return the value -1 instead of a valid file descriptor.

Where supported by the operating system, the implementation must set the file descriptor to be closed automatically when an execve system call is made.

Exporting a file descriptor from a fence may have side effects depending on the transference of the specified handle type, as described in Importing Fence State.

Valid Usage (Implicit)
  • device must be a valid VkDevice handle

  • pGetFdInfo must be a valid pointer to a valid VkFenceGetFdInfoKHR structure

  • pFd must be a valid pointer to an int value

Return Codes
On success, this command returns
  • VK_SUCCESS

On failure, this command returns
  • VK_ERROR_TOO_MANY_OBJECTS

  • VK_ERROR_OUT_OF_HOST_MEMORY

See Also

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 (c) 2014-2019 Khronos Group. This work is licensed under a Creative Commons Attribution 4.0 International License.