pthread_join hangs forever C++ - c++

Question

I am running this g_test where I simply initialize and close a client.
TEST(safIpc, createAndCloseClient)
{
std::shared_ptr<fnv::ipcsvc::IpcSvc> safIpc = std::make_shared<fnv::ipcsvc::IpcSvc>();
const std::string& app1 {"/testApp1"};
const std::string& groupName {"wir_clients"};
fnv::ipcsvc::IpcSvcAttrMq attr(fnv::ipcsvc::IpcSvcAttrType::MQ_CLIENT,
app1,
groupName,
"/server");
std::shared_ptr<IpcSvcTestSafHandler> msgHandler = std::make_shared<IpcSvcTestSafHandler>();
// initialize the ipc library
IpcSvcPriv::SharedPtr ipcPrivData {nullptr};
fnv::ipcsvc::IpcSvcRet ret = safIpc->init(attr, msgHandler, ipcPrivData);
EXPECT_EQ(ret, fnv::ipcsvc::IpcSvcRet::SUCCESS);
EXPECT_NE(ipcPrivData, nullptr);
ret = safIpc->close(ipcPrivData, app1); //HANGS here
EXPECT_EQ(fnv::ipcsvc::IpcSvcRet::SUCCESS, ret);
}
In init I create 3 threads: (here is the relevant part of the init code):
1- A process thread
2- a Receive thread
3- A timer thread
int rc = pthread_create(&m_timerThread,
NULL,
&IpcSvcImpl::timer_start,
this);
if (rc != 0)
{
ipcSvcLog(LOGE, "Failed to create timer thread!");
close(tmpPrivData,
attr.getAppId());
return error;
}
pthread_setname_np(m_timerThread,
"IpcSvcTimerThread");
}
// Start the worker threads
int rc = pthread_create(&m_receiveThread,
NULL,
&IpcSvcImpl::receive,
this);
if (rc != 0)
{
//TODO some error log
close(tmpPrivData,
attr.getAppId());
return error;
}
pthread_setname_np(m_receiveThread,
"IpcSvcReceiveThread");
rc = pthread_create(&m_processThread,
NULL,
&IpcSvcImpl::process,
this);
if (rc != 0)
{
//TODO some error log
close(tmpPrivData,
attr.getAppId());
return error;
}
pthread_setname_np(m_processThread,
"IpcSvcProcessThread");
Here is the close function:
IpcSvcRet IpcSvcImpl::close(IpcSvcPriv::SharedPtr privateData,
const std::string& appId)
{
if (!privateData)
{
//TODO log about client not providing sane private data
return IpcSvcRet::FAIL;
}
// acquire the mutex and set close called to true
{
std::lock_guard<std::mutex> guard(m_closeMtx);
m_closed = true;
}
if (m_msgQueue)
{
m_msgQueue->mutexInit();
// writing dummy message to process thread
std::pair<std::array<uint8_t, IPCSVC_MAX_MSG_SIZE>, ssize_t> queueMsg;
m_msgQueue->enqueue(queueMsg);
}
// writing dummy message to receive thread
uint32_t buffer = 0;
sendData(privateData,
(void*)&buffer,
sizeof(uint32_t),
appId);
pthread_join(m_receiveThread,
NULL);
pthread_join(m_processThread,
NULL);
if (m_isClient)
{
m_cv.notify_one();
printf("timer thread hangs\n"); // HANGS HERE ///////////////////////////////////////
pthread_join(m_timerThread,
NULL);
//This line is never reached..
}
delete m_msgQueue;
m_msgQueue = nullptr;
// close the ipc layer
if (m_ipc)
{
m_ipc->close();
delete m_ipc;
m_ipc = nullptr;
}
m_clientsList.clear();
m_hbManager = { };
return IpcSvcRet::SUCCESS;
}
Here is the timer_start function:
The timer thread is a timer that is keeps looping forever unless the fc->m_closed is set to true. It triggers fc->timerExpiry() every 2 seconds.
// timer thread entry
void* IpcSvcImpl::timer_start(void *arg)
{
if (!arg)
{
return nullptr;
}
printf("starting timer\n");
IpcSvcImpl* fc = static_cast<IpcSvcImpl *>(arg);
std::unique_lock<std::mutex> lock(fc->m_closeMtx);
while (!(fc->m_closed))
{
printf("Entering loop\n");
lock.unlock();
auto expireAt = std::chrono::steady_clock::now() +
std::chrono::seconds(fc->getTimerInterval());
fc->timerExpiry();
lock.lock();
printf("here?\n");
fc->m_cv.wait_until(lock, expireAt);
printf("Here 2\n");
}
printf("Exited loop\n\n");
return nullptr;
}
The output of the unittest:
[----------] 5 tests from safIpc
[ RUN ] safIpc.createAndCloseClient
starting timer
Entering loop
closing..
timer thread hangs
pthread join hangs forever, I am not sure why. The "here" prints are never hit, which seems odd.
Thanks for the help!