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pvar: Mutable variable with primitive values

[ bsd3, data, library ] [ Propose Tags ]

Mutable variable PVar that is backed by a single value MutableByteArray

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Versions [RSS] 0.1.0.0, 0.1.1.0, 0.2.0.0, 1.0.0.0
Change log CHANGELOG.md
Dependencies base (>=4.9 && <6), deepseq, primitive (>=0.7.1.0) [details]
License BSD-3-Clause
Copyright 2020 Alexey Kuleshevich
Author Alexey Kuleshevich
Maintainer alexey@kuleshevi.ch
Revised Revision 1 made by lehins at 2020-10-19T15:09:31Z
Category Data
Home page https://github.com/lehins/pvar#readme
Bug tracker https://github.com/lehins/pvar/issues
Source repo head: git clone https://github.com/lehins/pvar
Uploaded by lehins at 2020-10-19T15:00:28Z
Distributions LTSHaskell:1.0.0.0, NixOS:1.0.0.0, Stackage:1.0.0.0
Downloads 2369 total (51 in the last 30 days)
Rating 2.0 (votes: 1) [estimated by Bayesian average]
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Status Docs available [build log]
Last success reported on 2020-10-19 [all 1 reports]

Readme for pvar-1.0.0.0

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pvar

Interface for a mutable variable PVar that can hold values that have Prim instance.

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Package Hackage Nightly LTS
pvar Hackage Nightly Nightly

Overview

Main features include:

  • Performance. There is practically no overhead when compared to operating on pure values, although there is a higher memory overhead, since PVar is backed by a MutableByteArray#
  • Atomic operations for PVars with Int values. This includes a unique function that is not available in ghc-prim out of the box: 
atomicModifyIntPVar :: PrimMonad m => PVar m Int -> (Int -> (Int, a)) -> m a
  • Works in PrimMonad, therefore it is usable with ST, IO and various transformer monads.
  • Easy access to PVar contents with Storable
  • isByteArrayPinned, isMutableByteArrayPinned function that work on ghc-7.10 and ghc-8.0 as well as all the newer ones.