1 //===----------------------------------------------------------------------===//
2 //
3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
4 // See https://llvm.org/LICENSE.txt for license information.
5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
6 //
7 //===----------------------------------------------------------------------===//
8 //
9 // UNSUPPORTED: no-threads
10 // ALLOW_RETRIES: 2
11 
12 // <mutex>
13 
14 // class recursive_mutex;
15 
16 // bool try_lock();
17 
18 #include <mutex>
19 #include <thread>
20 #include <cstdlib>
21 #include <cassert>
22 
23 #include "make_test_thread.h"
24 #include "test_macros.h"
25 
26 std::recursive_mutex m;
27 
28 typedef std::chrono::system_clock Clock;
29 typedef Clock::time_point time_point;
30 typedef Clock::duration duration;
31 typedef std::chrono::milliseconds ms;
32 typedef std::chrono::nanoseconds ns;
33 
f()34 void f()
35 {
36     time_point t0 = Clock::now();
37     assert(!m.try_lock());
38     assert(!m.try_lock());
39     assert(!m.try_lock());
40     while(!m.try_lock())
41         ;
42     time_point t1 = Clock::now();
43     assert(m.try_lock());
44     m.unlock();
45     m.unlock();
46     ns d = t1 - t0 - ms(250);
47     assert(d < ms(200));  // within 200ms
48 }
49 
main(int,char **)50 int main(int, char**)
51 {
52     m.lock();
53     std::thread t = support::make_test_thread(f);
54     std::this_thread::sleep_for(ms(250));
55     m.unlock();
56     t.join();
57 
58   return 0;
59 }
60