libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/join.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
  11 // <thread>
  12
  13 // class thread
  14
  15 // void join();
  16
  17 #include <thread>
  18 #include <new>
  19 #include <cstdlib>
  20 #include <cassert>
  21 #include <system_error>
  22 #include <atomic>
  23
  24 #include "make_test_thread.h"
  25 #include "test_macros.h"
  26
  27 std::atomic_bool done(false);
  28
  29 class G
  30 {
  31     int alive_;
  32 public:
  33     static int n_alive;
  34     static bool op_run;
  35
  36     G() : alive_(1) {++n_alive;}
  37     G(const G& g) : alive_(g.alive_) {++n_alive;}
  38     ~G() {alive_ = 0; --n_alive;}
  39
  40     void operator()()
  41     {
  42         assert(alive_ == 1);
  43         assert(n_alive >= 1);
  44         op_run = true;
  45     }
  46 };
  47
  48 int G::n_alive = 0;
  49 bool G::op_run = false;
  50
  51 void foo() { done = true; }
  52
  53 int main(int, char**)
  54 {
  55     {
  56         G g;
  57         std::thread t0 = support::make_test_thread(g);
  58         assert(t0.joinable());
  59         t0.join();
  60         assert(!t0.joinable());
  61 #ifndef TEST_HAS_NO_EXCEPTIONS
  62         try {
  63             t0.join();
  64             assert(false);
  65         } catch (std::system_error const&) {
  66         }
  67 #endif
  68     }
  69 #ifndef TEST_HAS_NO_EXCEPTIONS
  70     {
  71         std::thread t0 = support::make_test_thread(foo);
  72         t0.detach();
  73         try {
  74             t0.join();
  75             assert(false);
  76         } catch (std::system_error const&) {
  77         }
  78         // Wait to make sure that the detached thread has started up.
  79         // Without this, we could exit main and start destructing global
  80         // resources that are needed when the thread starts up, while the
  81         // detached thread would start up only later.
  82         while (!done) {}
  83     }
  84 #endif
  85
  86   return 0;
  87 }