Difference between Barrier in C# 4.0 and WaitHandle in C# 3.0?

Question

I am picking up C# 4.0 and one of the things which is confusing me, is the barrier concept.

Is this not just like using the WaitAll method of WaitHandle

Answer 1

See Barrier. It waits for a group of multiple threads to reach certain point, instead of one. It is often used in scientific computing and simulation to represent time "ticks."

Imagine a 1000 x 1000 x 1000 grid of cubes representing cubic mile of air. At time zero a given unit cube gets affected by its neighbors' various parameters like temp and pressure. Once everyone computes time 1, you do the same for time 2... You get a weather simulation. Similar story for nuclear simulation.

There's also a variation of barrier called CyclicBarrier where it accepts threads that didn't take off from the start line and let it join back into the group after some time. It's not clear from the documentation whether C# 4's Barrier is a cyclic barrier, but there's a property called ParticipantsRemaining.