Crate mtl_sys 

Low-level Objective-C runtime bindings for Metal.

This crate provides the foundational FFI layer for communicating with the Objective-C runtime. It includes:

• Architecture-aware message sending (objc_msgSend variants)
• Selector and class caching
• Objective-C block support (Clang ABI)
• Custom macros for enums and bitflags

Safety

This crate is intentionally unsafe. All public functions are marked unsafe and require the caller to uphold Objective-C runtime invariants. Higher-level safe wrappers are provided by the metal crate.

Macros

class

Cached class lookup.

metal_enum

Define a Metal enum type.

metal_options

Define a Metal options/bitflags type.

sel

Cached selector lookup.

Structs

BlockLiteral

Block literal structure matching Clang’s Block_literal_1.

CachedClass

Helper type for caching classes.

CachedSel

Helper type for caching selectors.

Class

Objective-C class.

HeapOneArgBlock

A heap-allocated one-argument block that can be safely passed to ObjC APIs.

MethodDescription

Objective-C method description (for protocol methods).

Protocol

Objective-C protocol.

RcBlock

A reference-counted block wrapping a Rust closure.

Sel

Objective-C selector.

Enums

IOCompressionMethod

IO compression method.

IOCompressionStatus

IO compression status.

Functions

MTLCopyAllDevices^⚠

Copy all available Metal devices.

MTLCopyAllDevicesWithObserver^⚠

Copy all devices with a notification observer.

MTLCreateSystemDefaultDevice^⚠

Create the system default Metal device.

MTLIOCompressionContextAppendData^⚠

Append data to a compression context.

MTLIOCompressionContextDefaultChunkSize^⚠

Get the default chunk size for IO compression.

MTLIOCreateCompressionContext^⚠

Create an IO compression context.

MTLIOFlushAndDestroyCompressionContext^⚠

Flush and destroy a compression context.

MTLRemoveDeviceObserver^⚠

Remove a device observer.

copy_all_devices

Safely copy all available Metal devices (macOS only).

create_system_default_device

Safely create the system default Metal device.

get_protocol

Look up a protocol by name.

io_compression_default_chunk_size

Get the default IO compression chunk size.

msg_send_0^⚠

Send a message with no arguments.

msg_send_1^⚠

Send a message with 1 argument.

msg_send_2^⚠

Send a message with 2 arguments.

msg_send_3^⚠

Send a message with 3 arguments.

msg_send_4^⚠

Send a message with 4 arguments.

msg_send_5^⚠

Send a message with 5 arguments.

msg_send_6^⚠

Send a message with 6 arguments.

msg_send_7^⚠

Send a message with 7 arguments.

msg_send_8^⚠

Send a message with 8 arguments.

msg_send_9^⚠

Send a message with 9 arguments.

msg_send_10^⚠

Send a message with 10 arguments.

Type Aliases

CommandBufferHandler

Handler for command buffer completion.

DeallocatorBlock

Block type: void (^)(void*, size_t)

DeviceNotificationHandler

Handler for device notifications.

DeviceObserver

Opaque type for device observers (used with hot-plug notifications).

DrawablePresentedHandler

Handler for drawable presentation.

EventBlock

Block type: void (^)(id, uint64_t)

IOCompressionContext

Opaque compression context handle.

LogHandlerBlock

Block type: void (^)(id, id, isize, id)

NewComputePipelineStateCompletionHandler

Completion handler for compute pipeline state creation.

NewComputePipelineStateWithReflectionCompletionHandler

Completion handler for compute pipeline state with reflection.

NewLibraryCompletionHandler

Completion handler for library creation.

NewRenderPipelineStateCompletionHandler

Completion handler for render pipeline state creation.

NewRenderPipelineStateWithReflectionCompletionHandler

Completion handler for render pipeline state with reflection.

OneArgBlock

Block type: void (^)(id)

SharedEventNotificationHandler

Handler for SharedEvent notifications.

ThreeArgBlock

Block type: void (^)(id, id, id)

TwoArgBlock

Block type: void (^)(id, id)

VoidBlock

Block type: void (^)(void)