Struct VkOpaqueExportDesc 

pub struct VkOpaqueExportDesc {
    pub size: u64,
    pub memory_type_index: u32,
    pub offset: u64,
    pub dedicated: bool,
    pub width: u32,
    pub height: u32,
    pub format: PixelFormat,
    pub uuid: [u8; 16],
}

Available on Hermit or Unix or WASI or Windows only.

The producer-side export descriptor both native opaque-handle carriers carry — VkOpaqueFd on POSIX, VkOpaqueWin32 on Windows. (Those two are mutually-exclusive #[cfg]s, so they are named as plain code spans here rather than intra-doc links: no single rustdoc target can resolve both.)

One field per Vulkan source of truth, so a construction site reads as the vkGetMemory{Fd,Win32Handle}KHR ceremony it mirrors:

• Self::size — VkMemoryAllocateInfo::allocationSize.
• Self::memory_type_index — VkMemoryAllocateInfo::memoryTypeIndex.
• Self::offset — the vkBindImageMemory bind offset.
• Self::dedicated — whether the allocation chained VkMemoryDedicatedAllocateInfo.
• Self::width / Self::height — VkImageCreateInfo::extent.
• Self::format — the logical format behind VkImageCreateInfo::format.
• Self::uuid — VkPhysicalDeviceIDProperties::deviceUUID.

Why plain pub fields

The descriptor is inert metadata: the importer reads every field back verbatim to reconstruct a matching VkImageCreateInfo + VkMemoryDedicatedAllocateInfo chain. The invariants that can be checked without a live VkDevice (non-zero size, non-degenerate extent) are checked by the carrier constructors — which are the only way to build a carrier — and each carrier then stores its descriptor privately, exposing it only through by-value accessors. A validated carrier therefore cannot be edited back into an invalid one; the mutability stops at the constructor boundary.

Fields

size: u64

VkMemoryAllocateInfo::allocationSize of the exported VkDeviceMemory. Rejected when zero.

memory_type_index: u32

VkMemoryAllocateInfo::memoryTypeIndex of the exported VkDeviceMemory — on the exporting physical device, which for an opaque payload is by construction the importer’s own (the handle is only meaningful on the device whose Self::uuid this is).

Why this is not optional, and why the importer must not

re-derive it

For a payload created by the Vulkan API and carried over an opaque handle type, the import-side allocation must repeat the producer’s numbers exactly:

• VUID-VkMemoryAllocateInfo-allocationSize-01742 (VK_EXTERNAL_MEMORY_HANDLE_TYPE_OPAQUE_FD_BIT) and
• VUID-VkMemoryAllocateInfo-allocationSize-01743 (..._OPAQUE_WIN32_BIT / ..._OPAQUE_WIN32_KMT_BIT)

both read: “the values of allocationSize and memoryTypeIndex must match those specified when the payload being imported was created”. Sharing a physical device and intersecting memoryTypeBits do not relax that — an importer that re-runs its own “first device-local type” search can legally land on a different index than a producer that preferred, say, non-host-visible device-local memory, and the two disagree silently.

The importer also cannot recover the value from the driver: vkGetMemoryWin32HandlePropertiesKHR / vkGetMemoryFdPropertiesKHR are forbidden for opaque handle types (VUID-vkGetMemoryWin32HandlePropertiesKHR-handleType-00666, VUID-vkGetMemoryFdPropertiesKHR-handleType-00674). Carrying it on the descriptor is therefore the only correct channel.

A consumer should still validate what it receives — the index must be < VkPhysicalDeviceMemoryProperties::memoryTypeCount and must be set in its own image’s memoryTypeBits — and fall back rather than allocate when it is not.

offset: u64

Byte offset of the image inside the exported allocation — the memoryOffset the producer passed to vkBindImageMemory. 0 for the common single-image dedicated bind.

dedicated: bool

Mirrors VkMemoryDedicatedAllocateInfo — the importer MUST chain the matching VkMemoryDedicatedAllocateInfo if this is true.

width: u32

VkImageCreateInfo::extent.width. Rejected when zero.

height: u32

VkImageCreateInfo::extent.height. Rejected when zero.

format: PixelFormat

Logical format of the exported image. Single-plane exports of a multi-plane surface additionally stamp with_plane_format(..) on the carrier.

uuid: [u8; 16]

Source physical-device deviceUUID (VkPhysicalDeviceIDProperties::deviceUUID). The receiver’s VkPhysicalDevice MUST report the same UUID — opaque fd / NT-handle export is same-physical-device-only.

Trait Implementations

impl Clone for VkOpaqueExportDesc

fn clone(&self) -> Self

Returns a duplicate of the value.

fn clone_from(&mut self, source: &Self)

Performs copy-assignment from source.

impl Copy for VkOpaqueExportDesc

impl Debug for VkOpaqueExportDesc

fn fmt(&self, f: &mut Formatter<'_>) -> Result

Formats the value using the given formatter.

impl Eq for VkOpaqueExportDesc

impl PartialEq for VkOpaqueExportDesc

fn eq(&self, other: &Self) -> bool

Equality operator ==.

fn ne(&self, other: &Rhs) -> bool

Inequality operator !=.

impl StructuralPartialEq for VkOpaqueExportDesc