question about the semantics of unshared variables

[aki via Digitalmars-d-learn]

I noticed just making many threads cause an error.
Are there any limit for the number of threads?

import std.concurrency;
import core.thread;
void fun() { Thread.sleep(5000.msecs); }
void testThread() {
	foreach(i; 0..2000) {
		spawn(&fun);
	}
}

core.thread.ThreadError at src\core\thread.d(2903): Error creating 
thread

Aki.