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Structures

VkImportSemaphoreFdInfoKHR

Structure specifying POSIX file descriptor to import to a semaphore

The VkImportSemaphoreFdInfoKHR structure is defined as:

typedef struct VkImportSemaphoreFdInfoKHR {
    VkStructureType sType;
    const void* pNext;
    VkSemaphore semaphore;
    VkSemaphoreImportFlags flags;
    VkExternalSemaphoreHandleTypeFlagBits handleType;
    int fd;
} VkImportSemaphoreFdInfoKHR;
  • sType is a VkStructureType value identifying 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 is a VkExternalSemaphoreHandleTypeFlagBits value specifying the type of fd.
  • fd is the external handle to import.

The handle types supported by handleType are:

Handle TypeTransferencePermanence Supported
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BITReferenceTemporary,Permanent
VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_SYNC_FD_BITCopyTemporary

Valid Usage

VUID-VkImportSemaphoreFdInfoKHR-handleType-01143

handleType must be a value included in the Handle Types Supported by VkImportSemaphoreFdInfoKHR table

VUID-VkImportSemaphoreFdInfoKHR-fd-01544

fd must obey any requirements listed for handleType in external semaphore handle types compatibility

VUID-VkImportSemaphoreFdInfoKHR-handleType-03263

If handleType is VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT, the VkSemaphoreCreateInfo::flags field must match that of the semaphore from which fd was exported

VUID-VkImportSemaphoreFdInfoKHR-handleType-07307

If handleType refers to a handle type with copy payload transference semantics, flags must contain VK_SEMAPHORE_IMPORT_TEMPORARY_BIT

VUID-VkImportSemaphoreFdInfoKHR-handleType-03264

If handleType is VK_EXTERNAL_SEMAPHORE_HANDLE_TYPE_OPAQUE_FD_BIT, the VkSemaphoreTypeCreateInfo::semaphoreType field must match that of the semaphore from which fd was exported

VUID-VkImportSemaphoreFdInfoKHR-flags-03323

If flags contains VK_SEMAPHORE_IMPORT_TEMPORARY_BIT, the VkSemaphoreTypeCreateInfo::semaphoreType field of the semaphore from which fd was exported must not be VK_SEMAPHORE_TYPE_TIMELINE

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.

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)

VUID-VkImportSemaphoreFdInfoKHR-sType-sType

sType must be VK_STRUCTURE_TYPE_IMPORT_SEMAPHORE_FD_INFO_KHR

VUID-VkImportSemaphoreFdInfoKHR-pNext-pNext

pNext must be NULL

VUID-VkImportSemaphoreFdInfoKHR-semaphore-parameter

semaphore must be a valid VkSemaphore handle

VUID-VkImportSemaphoreFdInfoKHR-flags-parameter

flags must be a valid combination of VkSemaphoreImportFlagBits values

VUID-VkImportSemaphoreFdInfoKHR-handleType-parameter

handleType must be a valid VkExternalSemaphoreHandleTypeFlagBits value

Host Synchronization

  • Host access to semaphore must be externally synchronized