LC_SLEEPABLE
.lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_SLEEPABLE
.lc_flags = LC_SLEEPLOCK | LC_SLEEPABLE | LC_UPGRADABLE
.lc_flags = LC_SLEEPLOCK | LC_RECURSABLE | LC_SLEEPABLE |
(class->lc_flags & LC_SLEEPABLE) == 0)