# VK_FUCHSIA_external_semaphore(3) Manual Page

## Name

VK_FUCHSIA_external_semaphore - device extension

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## Registered Extension Number

366

## Revision

1

## Ratification Status

Not ratified

## Extension and Version Dependencies

VK_KHR_external_semaphore_capabilities
and
VK_KHR_external_semaphore

## Contact

- John Rosasco [GitHub]rosasco

## Other Extension Metadata

Last Modified Date

  2021-03-08

IP Status

  No known IP claims.

Contributors

  - Craig Stout, Google

  - John Bauman, Google

  - John Rosasco, Google

## Description

An application using external memory may wish to synchronize access to that memory using semaphores. This extension enables an application to export semaphore payload to and import semaphore payload from Zircon event handles.

## New Commands

- vkGetSemaphoreZirconHandleFUCHSIA

- vkImportSemaphoreZirconHandleFUCHSIA

## New Structures

- VkImportSemaphoreZirconHandleInfoFUCHSIA

- VkSemaphoreGetZirconHandleInfoFUCHSIA

## New Enum Constants

- `VK_FUCHSIA_EXTERNAL_SEMAPHORE_EXTENSION_NAME`

- `VK_FUCHSIA_EXTERNAL_SEMAPHORE_SPEC_VERSION`

- Extending VkExternalSemaphoreHandleTypeFlagBits:

  - `VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_ZIRCON_EVENT_BIT_FUCHSIA`

- Extending VkStructureType:

  - `VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_ZIRCON_HANDLE_INFO_FUCHSIA`

  - `VK_STRUCTURE_TYPE_SEMAPHORE_GET_ZIRCON_HANDLE_INFO_FUCHSIA`

## Issues

1) Does the application need to close the Zircon event handle returned by vkGetSemaphoreZirconHandleFUCHSIA?

RESOLVED: Yes, unless it is passed back in to a driver instance to import the semaphore. A successful get call transfers ownership of the Zircon event handle to the application, and a successful import transfers it back to the driver. Destroying the original semaphore object will not close the Zircon event handle nor remove its reference to the underlying semaphore resource associated with it.

## Version History

- Revision 1, 2021-03-08 (John Rosasco)

  - Initial revision

## See Also

No cross-references are available

## Document Notes

For more information, see the Vulkan Specification

This page is a generated document. Fixes and changes should be made to the generator scripts, not directly.

## Copyright

Copyright 2014-2024 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0