semaphore-compat: Cross-platform abstraction for system semaphores

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Cross-platform semaphores for managing resources across processes, abstracting over Win32 named semaphores on Windows and Unix domain sockets on POSIX.

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System
- System.Semaphore
  - Internal
    - System.Semaphore.Internal.Common
    - System.Semaphore.Internal.DomainSocket
    - System.Semaphore.Internal.Posix
    - System.Semaphore.Internal.Unsupported
    - System.Semaphore.Internal.Win32

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semaphore-compat-2.0.0.tar.gz [browse] (Cabal source package)
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BenGamari, mpickering, wz1000, sheaf

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Versions [RSS]	1.0.0, 2.0.0
Change log	changelog.md
Dependencies	base (>=4.11 && <4.23), containers (>=0.5 && <0.9), directory (>=1.3 && <1.4), exceptions (>=0.7 && <0.11), filepath (>=1.4 && <1.6), process (>=1.6.16 && <1.8), semaphore-compat, stm (>=2.4 && <2.6), unix (>=2.8.1.0 && <2.9), Win32 (>=2.13.4.0 && <2.15) [details]
License	BSD-3-Clause
Author	The GHC team
Maintainer	ghc-devs@haskell.org
Uploaded	by wz1000 at 2026-05-25T10:36:08Z
Category	System
Home page	https://gitlab.haskell.org/ghc/semaphore-compat
Bug tracker	https://gitlab.haskell.org/ghc/ghc/issues/new
Source repo	head: git clone https://gitlab.haskell.org/ghc/semaphore-compat.git
Distributions	Fedora:1.0.0
Reverse Dependencies	4 direct, 15985 indirect [details]
Executables	semaphore-helper
Downloads	1540 total (5 in the last 30 days)
Rating	(no votes yet) [estimated by Bayesian average]
Your Rating	λ λ λ
Status	Docs available [build log] Last success reported on 2026-05-25 [all 1 reports]

Readme for semaphore-compat-2.0.0

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semaphore-compat

semaphore-compat provides cross-platform semaphores that can be shared across processes.

It uses different backends on different platforms:

POSIX: Unix domain sockets with automatic return of tokens from disconnected clients.
Windows: Win32 named semaphores. Tokens held by crashed clients are not returned automatically.
wasm/JavaScript: buildable stubs that throw unsupported-operation errors. Avoid calling this code on these backends.

It supports:

Creating server semaphores (createSemaphore, freshSemaphore).
- A server is the process that creates the semaphore and must stay alive for the duration of its use.
- A server process can also act as a client and request/release tokens from the semaphore.
Opening client semaphores (openSemaphore).
Waiting with tryWaitOnSemaphore or interruptible waitOnSemaphore, which return SemaphoreTokens.
Releasing tokens with releaseSemaphoreToken or withSemaphoreToken.
Destroying semaphores with destroyClientSemaphore and destroyServerSemaphore.
Serialising names and checking versions with semaphoreIdentifier and versionsAreCompatible.