llvm-project/libcxx/test/std/thread/thread.threads/thread.thread.class/thread.thread.member/detach.pass.cpp

//===----------------------------------------------------------------------===//
//
//                     The LLVM Compiler Infrastructure
//
// This file is dual licensed under the MIT and the University of Illinois Open
// Source Licenses. See LICENSE.TXT for details.
//
//===----------------------------------------------------------------------===//
//
// UNSUPPORTED: libcpp-has-no-threads

// <thread>

// class thread

// void detach();

#include <thread>
#include <atomic>
#include <system_error>
#include <cassert>

#include "test_macros.h"

std::atomic_bool done(false);

class G
{
    int alive_;
    bool done_;
public:
    static int n_alive;
    static bool op_run;

    G() : alive_(1), done_(false)
    {
        ++n_alive;
    }

    G(const G& g) : alive_(g.alive_), done_(false)
    {
        ++n_alive;
    }
    ~G()
    {
        alive_ = 0;
        --n_alive;
        if (done_) done = true;
    }

    void operator()()
    {
        assert(alive_ == 1);
        assert(n_alive >= 1);
        op_run = true;
        done_ = true;
    }
};

int G::n_alive = 0;
bool G::op_run = false;

void foo() {}

int main()
{
    {
        G g;
        std::thread t0(g);
        assert(t0.joinable());
        t0.detach();
        assert(!t0.joinable());
        while (!done) {}
        assert(G::op_run);
        assert(G::n_alive == 1);
    }
    assert(G::n_alive == 0);
#ifndef TEST_HAS_NO_EXCEPTION
    {
        std::thread t0(foo);
        assert(t0.joinable());
        t0.detach();
        assert(!t0.joinable());
        try {
            t0.detach();
        } catch (std::system_error const& ec) {
        }
    }
#endif
}