NAME
	DupLock -- Duplicate a lock

    SYNOPSIS
	lock = DupLock( lock )
	D0		D1

	BPTR DupLock(BPTR)

    FUNCTION
	DupLock() is passed a shared filing system lock.  This is the ONLY
	way to obtain a duplicate of a lock... simply copying is not
	allowed.

	Another lock to the same object is then returned.  It is not
	possible to create a copy of a exclusive lock.

	A zero return indicates failure.

    INPUTS
	lock - BCPL pointer to a lock

    RESULTS
	newLock - BCPL pointer to a lock

    SEE ALSO
	Lock(), UnLock(), DupLockFromFH(), ParentOfFH()