Use *NSYNC for POSIX threads locking APIs

Condition variables, barriers, and r/w locks now work very well.

test/libc/thread/pthread_cond_signal_test.c

@@ -0,0 +1,118 @@
+/*-*- mode:c;indent-tabs-mode:nil;c-basic-offset:2;tab-width:8;coding:utf-8 -*-│
+│vi: set net ft=c ts=2 sts=2 sw=2 fenc=utf-8                                :vi│
+╞══════════════════════════════════════════════════════════════════════════════╡
+│ Copyright 2022 Justine Alexandra Roberts Tunney                              │
+│                                                                              │
+│ Permission to use, copy, modify, and/or distribute this software for         │
+│ any purpose with or without fee is hereby granted, provided that the         │
+│ above copyright notice and this permission notice appear in all copies.      │
+│                                                                              │
+│ THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL                │
+│ WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED                │
+│ WARRANTIES OF MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE             │
+│ AUTHOR BE LIABLE FOR ANY SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL         │
+│ DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR        │
+│ PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER               │
+│ TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR             │
+│ PERFORMANCE OF THIS SOFTWARE.                                                │
+╚─────────────────────────────────────────────────────────────────────────────*/
+#include "libc/calls/struct/timespec.h"
+#include "libc/errno.h"
+#include "libc/testlib/testlib.h"
+#include "libc/thread/thread.h"
+#include "libc/thread/thread2.h"
+
+int pos;
+int count;
+int limit;
+long data[1000];
+pthread_mutex_t mu;
+pthread_cond_t non_full;
+pthread_cond_t non_empty;
+
+int Put(long v, struct timespec *abs_deadline) {
+  int err, added = 0, wake = 0;
+  pthread_mutex_lock(&mu);
+  while (count == limit) {
+    if ((err = pthread_cond_timedwait(&non_full, &mu, abs_deadline))) {
+      ASSERT_EQ(ETIMEDOUT, err);
+      ASSERT_NE(NULL, abs_deadline);
+    }
+  }
+  if (count != limit) {
+    int i = pos + count;
+    if (limit <= i) i -= limit;
+    data[i] = v;
+    if (count == 0) wake = 1;
+    count++;
+    added = 1;
+  }
+  pthread_mutex_unlock(&mu);
+  if (wake) pthread_cond_broadcast(&non_empty);
+  return added;
+}
+
+long Get(struct timespec *abs_deadline) {
+  long err, v = 0;
+  pthread_mutex_lock(&mu);
+  while (!count) {
+    if ((err = pthread_cond_timedwait(&non_empty, &mu, abs_deadline))) {
+      ASSERT_EQ(ETIMEDOUT, err);
+      ASSERT_NE(NULL, abs_deadline);
+    }
+  }
+  if (count) {
+    v = data[pos];
+    data[pos] = 0;
+    if (count == limit) {
+      pthread_cond_broadcast(&non_full);
+    }
+    pos++;
+    count--;
+    if (pos == limit) {
+      pos = 0;
+    }
+  }
+  pthread_mutex_unlock(&mu);
+  return v;
+}
+
+#define N 10000
+
+void *Producer(void *arg) {
+  for (int i = 0; i < N; i++) {
+    ASSERT_EQ(1, Put((i + 1) * 3, 0));
+  }
+  return 0;
+}
+
+void *Consumer(void *arg) {
+  for (int i = 0; i < N; i++) {
+    ASSERT_EQ((i + 1) * 3, Get(0));
+  }
+  return 0;
+}
+
+TEST(cond, test) {
+  pthread_t t;
+
+  limit = 1;
+  ASSERT_EQ(0, pthread_create(&t, 0, Producer, 0));
+  Consumer(0);
+  ASSERT_EQ(0, pthread_join(t, 0));
+
+  limit = 10;
+  ASSERT_EQ(0, pthread_create(&t, 0, Producer, 0));
+  Consumer(0);
+  ASSERT_EQ(0, pthread_join(t, 0));
+
+  limit = 100;
+  ASSERT_EQ(0, pthread_create(&t, 0, Producer, 0));
+  Consumer(0);
+  ASSERT_EQ(0, pthread_join(t, 0));
+
+  limit = 1000;
+  ASSERT_EQ(0, pthread_create(&t, 0, Producer, 0));
+  Consumer(0);
+  ASSERT_EQ(0, pthread_join(t, 0));
+}