jcs.org
Serenity Operating System
1/*
2 * Copyright (c) 2018-2020, the SerenityOS developers.
3 *
4 * SPDX-License-Identifier: BSD-2-Clause
5 */
6
7#include <cassert>
8#include <cstring>
9#include <ctime>
10#include <errno.h>
11#include <pthread.h>
12#include <stdio.h>
13#include <stdlib.h>
14#include <unistd.h>
15
16struct worker_t {
17 char const* name;
18 int count;
19 pthread_t thread;
20 pthread_mutex_t lock;
21 pthread_cond_t cond;
22 long int wait_time;
23};
24
25static void* run_worker(void* args)
26{
27 struct timespec time_to_wait = { 0, 0 };
28 worker_t* worker = (worker_t*)args;
29 worker->count = 0;
30
31 while (worker->count < 25) {
32 time_to_wait.tv_sec = time(nullptr) + worker->wait_time;
33 pthread_mutex_lock(&worker->lock);
34 int rc = pthread_cond_timedwait(&worker->cond, &worker->lock, &time_to_wait);
35
36 // Validate return code is always timed out.
37 assert(rc == -1);
38 assert(errno == ETIMEDOUT);
39
40 worker->count++;
41 printf("Increase worker[%s] count to [%d]\n", worker->name, worker->count);
42 pthread_mutex_unlock(&worker->lock);
43 }
44
45 return nullptr;
46}
47
48static void init_worker(worker_t* worker, char const* name, long int wait_time)
49{
50 worker->name = name;
51 worker->wait_time = wait_time;
52
53 pthread_attr_t attr;
54 pthread_attr_init(&attr);
55 pthread_attr_setdetachstate(&attr, PTHREAD_CREATE_JOINABLE);
56
57 pthread_mutex_init(&worker->lock, nullptr);
58 pthread_cond_init(&worker->cond, nullptr);
59 pthread_create(&worker->thread, &attr, &run_worker, (void*)worker);
60
61 pthread_attr_destroy(&attr);
62}
63
64int main()
65{
66 worker_t worker_a;
67 init_worker(&worker_a, "A", 2L);
68
69 worker_t worker_b;
70 init_worker(&worker_b, "B", 4L);
71
72 pthread_join(worker_a.thread, nullptr);
73 pthread_join(worker_b.thread, nullptr);
74
75 return EXIT_SUCCESS;
76}