C Specification

The VkImportSemaphoreFdInfoKHR structure is defined as:

// Provided by VK_KHR_external_semaphore_fd
typedef struct VkImportSemaphoreFdInfoKHR {
    VkStructureType                          sType;
    const void*                              pNext;
    VkSemaphore                              semaphore;
    VkSemaphoreImportFlags                   flags;
    VkExternalSemaphoreHandleTypeFlagBits    handleType;
    int                                      fd;
} VkImportSemaphoreFdInfoKHR;

Members

  • sType is the type of this structure.

  • pNext is NULL or a pointer to a structure extending this structure.

  • semaphore is the semaphore into which the payload will be imported.

  • flags is a bitmask of VkSemaphoreImportFlagBits specifying additional parameters for the semaphore payload import operation.

  • handleType specifies the type of fd.

  • fd is the external handle to import.

Description

The handle types supported by handleType are:

Table 1. Handle Types Supported by VkImportSemaphoreFdInfoKHR
Handle Type Transference Permanence Supported

VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT

Reference

Temporary,Permanent

VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT

Copy

Temporary

Valid Usage

If handleType is VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT, the special value -1 for fd is treated like a valid sync file descriptor referring to an object that has already signaled. The import operation will succeed and the VkSemaphore will have a temporarily imported payload as if a valid file descriptor had been provided.

Note

This special behavior for importing an invalid sync file descriptor allows easier interoperability with other system APIs which use the convention that an invalid sync file descriptor represents work that has already completed and does not need to be waited for. It is consistent with the option for implementations to return a -1 file descriptor when exporting a VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BIT from a VkSemaphore which is signaled.

Valid Usage (Implicit)
Host Synchronization
  • Host access to semaphore must be externally synchronized

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) 2014-2020 The Khronos Group Inc.

SPDX-License-Identifier: CC-BY-4.0