id	summary	reporter	owner	description	type	status	priority	milestone	component	version	resolution	keywords	cc	os	architecture	failure	difficulty	testcase	blockedby	blocking	related
1048	Add forkIO that starts in 'block' mode	ChrisKuklewicz	simonmar	"The current forkIO starts in 'unblock' mode and the spawned thread can receive asynchronous exceptions (and die) before the passed (IO ()) action can start to run.

Even if the user tried (forkIO (block io)) the new thread can be killed before entering the scope of block.

Proposal: Add forkBlockedIO that spawns the new thread in a 'block' state.
Alternative: Add forkInheritIO that spawns the new thread in the same block or unblock state as the parent thread is at the forkInheritIO call.  Thus (forkBlockedIO = block . forkInheritIO) and (forkIO = unblock . forkInheritIO).

Work around: At the moment a fresh MVar can immediately be used by the parent to wait until the child has signaled that it is executing withing the scope of the block (or exception handler, etc).

This ought to also be extended to forkBlockedOS or forkInheritOS."	feature request	closed	normal	6.10 branch	libraries/base	6.6	fixed	concurrency		Unknown/Multiple	Unknown/Multiple		Easy (less than 1 hour)