@hackage / lukko

File locking

Latest0.1.2

About

Metadata

  • Last updated , by phadej
  • License GPL-2.0-or-later AND BSD-3-Clause
  • Categories Systems Programming, Concurrency

  • Maintained by: Oleg Grenrus <oleg.grenrus@iki.fi>

  • Lottery factor: 1

Links

Installation

Tested Compilers

  1. 9.12.1
  2. 9.10.1
  3. 9.8.4
  4. 9.6.6
  5. 9.4.8
  6. 9.2.8
  7. 9.0.2
  8. 8.10.7
  9. 8.8.4
  10. 8.6.5

Package Flags

Use the -f option with cabal commands to enable flags

    ofd-locking (on by default)

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

Readme

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.