lukko

File locking

LTS Haskell 24.16:0.1.2@rev:1
Stackage Nightly 2025-10-24:0.1.2@rev:1
Latest on Hackage:0.1.2@rev:1

See all snapshots lukko appears in

GPL-2.0-or-later AND BSD-3-Clause licensed
Maintained by Oleg Grenrus
This version can be pinned in stack with:lukko-0.1.2@sha256:8334a8d810e385e1dc1423dc02945daaa1f1a9ba058e5227f1a3211e4882ca28,4473

Module documentation for 0.1.2

Depends on 1 package(full list with versions):
base
Used by 1 package in nightly-2025-10-24(full list with versions):
cabal-install

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.

Changes

0.1.2

  • Support GHC-8.6.5…9.10.1

0.1.1.3

  • Use CApiFFI to call varargs C functions.
  • Define let alignment only when needed.

0.1.1.2

  • Make Win32 code more idiomatic

0.1.1.1

  • Add proper Setup.hs

0.1.1

  • Add Setup.hs to sdist
  • Add type-level FileLockingSupported