libcxx/test/std/thread/thread.mutex/thread.lock/thread.lock.shared/thread.lock.shared.locking/try_lock.pass.cpp

   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 // UNSUPPORTED: c++03, c++11
  11 //
  12 // ALLOW_RETRIES: 2
  13
  14 // <shared_mutex>
  15
  16 // template <class Mutex> class shared_lock;
  17
  18 // bool try_lock();
  19
  20 #include <cassert>
  21 #include <mutex>
  22 #include <shared_mutex>
  23 #include <system_error>
  24
  25 #include "test_macros.h"
  26
  27 bool try_lock_called = false;
  28
  29 struct mutex
  30 {
  31     bool try_lock_shared()
  32     {
  33         try_lock_called = !try_lock_called;
  34         return try_lock_called;
  35     }
  36     void unlock_shared() {}
  37 };
  38
  39 mutex m;
  40
  41 int main(int, char**)
  42 {
  43     std::shared_lock<mutex> lk(m, std::defer_lock);
  44     assert(lk.try_lock() == true);
  45     assert(try_lock_called == true);
  46     assert(lk.owns_lock() == true);
  47 #ifndef TEST_HAS_NO_EXCEPTIONS
  48     try
  49     {
  50         TEST_IGNORE_NODISCARD lk.try_lock();
  51         assert(false);
  52     }
  53     catch (std::system_error& e)
  54     {
  55         assert(e.code().value() == EDEADLK);
  56     }
  57 #endif
  58     lk.unlock();
  59     assert(lk.try_lock() == false);
  60     assert(try_lock_called == false);
  61     assert(lk.owns_lock() == false);
  62     lk.release();
  63 #ifndef TEST_HAS_NO_EXCEPTIONS
  64     try
  65     {
  66         TEST_IGNORE_NODISCARD lk.try_lock();
  67         assert(false);
  68     }
  69     catch (std::system_error& e)
  70     {
  71         assert(e.code().value() == EPERM);
  72     }
  73 #endif
  74
  75   return 0;
  76 }