@hackage lukko0.1.2

File locking

Categories
- Systems Programming
- Concurrency
License
GPL-2.0-or-later AND BSD-3-Clause
Maintainer
Oleg Grenrus <oleg.grenrus@iki.fi>
Links
Versions
- 0.1.2 Sun, 5 Jan 2025
- 0.1.1.3 Fri, 13 Oct 2023
- 0.1.1.2 Wed, 25 Mar 2020
- 0.1.1.1 Sat, 16 Nov 2019
- 0.1.1 Thu, 14 Nov 2019
- 0.1 Sat, 2 Nov 2019

Installation
In your cabal file:
Tested Compilers
Dependencies (1)
- base >=4.12.0.0 && <4.22
Dependents (6)
@hackage/hackage-security, @hackage/cabal-install-parsers, @hackage/cabal-install, @hackage/hackport, @hackage/cachix, @hackage/ghc-tags-plugin

Package Flags

ofd-locking

(on by default)

Enable open file descriptor locking. Available on Linux (kernel 3.15, released Jun 8, 2014).

This package provides access to platform dependent file locking APIs:

Open file descriptor locking on Linux (Lukko.OFD)
BSD-style flock(2) locks on UNIX platforms (Lukko.FLock)
Windows locking via LockFileEx (Lukko.Windows)
No-op locking, which throws exceptions (Lukko.NoOp)
Lukko module exports the best option for the target platform with uniform API.

There are alternative file locking packages:

GHC.IO.Handle.Lock in base >= 4.10 is good enough for most use cases. However, uses only Handles so these locks cannot be used for intra-process locking. (You should use e.g. MVar in addition).
filelock doesn't support OFD locking.

Lukko means lock in Finnish.

Submodules Lukko.OFD, Lukko.Windows etc are available based on following conditions.

if os(windows)
  cpp-options: -DHAS_WINDOWS_LOCK

elif (os(linux) && flag(ofd-locking))
  cpp-options: -DHAS_OFD_LOCKING
  cpp-options: -DHAS_FLOCK

elif !(os(solaris) || os(aix))
  cpp-options: -DHAS_FLOCK

Lukko.FLock is available on not (Windows or Solaris or AIX). Lukko.NoOp is always available.