Implement POSIX threads API

libc/thread/pthread_cond_wait.c

@@ -0,0 +1,47 @@
+/*-*- 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/intrin/pthread2.h"
+
+/**
+ * Waits for condition, e.g.
+ *
+ *     pthread_cond_t cond = PTHREAD_COND_INITIALIZER;
+ *     pthread_mutex_t lock = PTHREAD_MUTEX_INITIALIZER;
+ *
+ *     // waiting threads
+ *     pthread_mutex_lock(&lock);
+ *     pthread_cond_wait(&cond, &lock);
+ *     pthread_mutex_unlock(&lock);
+ *
+ *     // notifying thread
+ *     pthread_mutex_lock(&lock);
+ *     pthread_cond_broadcast(&cond);
+ *     pthread_mutex_unlock(&lock);
+ *
+ * @param mutex needs to be held by thread when calling this function
+ * @return 0 on success, or errno on error
+ * @raise EPERM if `mutex` is `PTHREAD_MUTEX_ERRORCHECK` and the lock
+ *     isn't owned by the current thread
+ * @see pthread_cond_timedwait
+ * @see pthread_cond_broadcast
+ * @see pthread_cond_signal
+ */
+int pthread_cond_wait(pthread_cond_t *cond, pthread_mutex_t *mutex) {
+  return pthread_cond_timedwait(cond, mutex, 0);
+}