ref: 23156b142baa61ea67cec46d7f4da141c19f91bd
dir: /lib/thread/condvar.myr/
use std use "atomic" use "common" use "mutex" use "sem" pkg thread = type cond = struct _mtx : mutex# _head : condwaiter# _tail : condwaiter# _lock : mutex ;; const mkcond : (mtx : mutex# -> cond) const condwait : (cond : cond# -> void) const condsignal : (cond : cond# -> void) const condbroadcast : (cond : cond# -> void) ;; type condwaiter = struct next : condwaiter# sem : sem ;; const mkcond = {mtx -> [._mtx = mtx, ._lock = mkmtx()] } const condwait = {cond var mtx = cond._mtx var lock = &cond._lock var waiter = std.mk([.sem = mksem(0)]) mtxlock(lock) match cond._tail | Zptr: cond._head = cond._tail = waiter | tail: cond._tail = tail.next = waiter ;; mtxunlock(lock) mtxunlock(mtx) semwait(&waiter.sem) std.free(waiter) mtxlock(mtx) } const condsignal = {cond var lock = &cond._lock mtxlock(lock) var head = cond._head if head != Zptr cond._head = head.next sempost(&head.sem) if cond._head == Zptr cond._tail = Zptr ;; ;; mtxunlock(lock) } /* Yes, this invites the thundering herd but that's what you get for not supporting futexes at all. */ const condbroadcast = {cond var lock = &cond._lock var head = Zptr mtxlock(lock) while (head = cond._head) != Zptr cond._head = head.next sempost(&head.sem) ;; cond._tail = Zptr mtxunlock(lock) }