Concurrency demos

This page collects examples of concurrent and parallel programming in Haskell.

Examples

• Riemann's Zeta function approximation
• Signal that you want to gracefully exit another thread
• Passing messages across a single chan to two readers
• Chat server - using a single channel for a variable number of readers
• Passing IO events lazily from a producer to a consumer thread

More examples

A large range of small demonstration programs for using concurrent and parallel Haskell are in the Haskell concurrency regression tests. In particular, they show the use of MVars and forkIO.

Proposed updates

The base 3.0.3.1 package's Control.Concurrent.QSem and QSemN are not exception safe. The SafeConcurrent has the proposed replacement code.

Other examples

• Haskell -> Javascript: Pseudo-concurrent threads in web browser