[][src]Crate ulock_sys

Bindings for macOS's not-entirely-public ulock API, which provides futex-like functionality.

In general, caveat emptor. It's recommended that you read both the source and the header. In particular, I've not documented the code very much beyond what's in the headers, aside from supported version indications.


This API is available on darwin 16+ (macOS 10.12+, iOS 10.0+, tvOS 10.0+, watchOS 3.0+, catalyst 13.0+), although some parts are darwin 19+ (macOS 10.15+, iOS 13.0+, TODO: find out the rest). The parts on darwin 19+ are in the darwin19 module (it's just some additional constants, so not worth feature gating).

That is to say, this is pretty well supported, over 95% of users on both macOS and iOS will have it (according to statscounter as of Jan 2021).

That said, they're not public, and who knows the future, maybe Apple will remove them. But probably not — they're also used by libc++, and so if they ever went away, code that statically links libc++ would suddenly break, but... who knows, maybe apple will do it.

"weak" linking, cargo features

As a result of that (and so that you can support older versions), if you enable the experimental-weak feature, we'll expose a module weak which emulates weak linking and accesses the function via dlsym.

Note that on aarch64 darwin (e.g. "apple silicon", the ARM64 macbooks and such) by default we don't dlsym even if the "experimental-weakweak" feature is on unless "weak-aarch64-macos" is also specified. This is because all OSes on these machines support the API. This can be overridden by enabling the weak-aarch64-macos feature.

Note that the API of this crate (except for consts) is behind cfg!(target_vendor = "apple").



The portion of the API only is supported on Darwin 19 and up (macOS 10.15+, iOS 13.0+).


feature = "experimental-weak" Weak linking emulation. See crate docs for info.



Generic flag usable with __ulock_wake or __ulock_wait (these are in bits 24-32)


Flag only for __ulock_wait (these are in bits 16-24).


Flag for __ulock_wait (these are in bits 16-24).


Flag for __ulock_wake (these are in bits 8-16)


Flag for __ulock_wake (these are in bits 8-16)


Operation code (these are in bits 0-8)


Obsolete name for UL_UNFAIR_LOCK. Deprecated, but provided for porting.


Obsolete name for UL_COMPARE_AND_WAIT. Deprecated, but provided for porting.


Operation code (these are in bits 0-8)



Type Definitions


Alias for the function pointer of __ulock_wait.


Alias for the function pointer of __ulock_wake.