atomic-counter-0.1.2.3: Mutable counters that can be modified with atomic operatinos
Copyright(c) Sergey Vinokurov 2022
LicenseApache-2.0 (see LICENSE)
Maintainerserg.foo@gmail.com
Safe HaskellSafe-Inferred
LanguageHaskell2010

Control.Concurrent.Counter

Description

Work with lifted Counter values in the IO monad. Please see other modules in this package for ST monad and for unlifted values.

Synopsis

Documentation

data Counter Source #

Memory location that supports select few atomic operations.

Isomorphic to IORef Int.

Instances

Instances details
Eq Counter Source #

Pointer equality

Instance details

Defined in Control.Concurrent.Counter.Lifted.IO

Methods

(==) :: Counter -> Counter -> Bool #

(/=) :: Counter -> Counter -> Bool #

Create

new :: Int -> IO Counter Source #

Create new counter with initial value.

Read/write

get :: Counter -> IO Int Source #

Atomically read the counter's value.

set :: Counter -> Int -> IO () Source #

Atomically assign new value to the counter.

cas Source #

Arguments

:: Counter 
-> Int

Expected old value

-> Int

New value

-> IO Int 

Atomic compare and swap, i.e. write the new value if the current value matches the provided old value. Returns the value of the element before the operation

Arithmetic operations

add :: Counter -> Int -> IO Int Source #

Atomically add an amount to the counter and return its old value.

sub :: Counter -> Int -> IO Int Source #

Atomically subtract an amount from the counter and return its old value.

Bitwise operations

and :: Counter -> Int -> IO Int Source #

Atomically combine old value with a new one via bitwise and. Returns old counter value.

or :: Counter -> Int -> IO Int Source #

Atomically combine old value with a new one via bitwise or. Returns old counter value.

xor :: Counter -> Int -> IO Int Source #

Atomically combine old value with a new one via bitwise xor. Returns old counter value.

nand :: Counter -> Int -> IO Int Source #

Atomically combine old value with a new one via bitwise nand. Returns old counter value.