# question mark operator on semaphore operation.
resource qm8()
    op semop() {send}

    write(?semop)
    send semop()
    send semop()
    send semop()
    send semop()
    send semop()
    write(?semop)
    while (?semop != 0) {
	write("receiving", ?semop)
	receive semop()
    }
end
