FT_SetEventNotification on Linux

I have three different java threads opening three Serial Devices. I am just curious if I have to create EVENT_HANDLE eh for each thread (local variable) inside read function or just a Global variable outside of the read Data function. And pthread_cond_wait(&eh.eCondVar, &eh.eMutex); is a critical section according to the example below provided in the link https://www.ftdichip.com/Support/Knowledgebase/index.html?ft_seteventnotification.htm for Linux operating system. I am trying to understand if I have to do the same locking mechanism because I am only doing one read at a time from each of my java threads. Please provide some inputs.

FT_HANDLE ftHandle; 
FT_STATUS ftStatus;
EVENT_HANDLE eh;
DWORD EventMask;

ftStatus = FT_Open(0, &ftHandle);
if(ftStatus != FT_OK) {
   // FT_Open failed
   return;
}

pthread_mutex_init(&eh.eMutex, NULL);
pthread_cond_init(&eh.eCondVar, NULL);

EventMask = FT_EVENT_RXCHAR | FT_EVENT_MODEM_STATUS;
ftStatus = FT_SetEventNotification(ftHandle, EventMask, (PVOID)&eh);

pthread_mutex_lock(&eh.eMutex);
pthread_cond_wait(&eh.eCondVar, &eh.eMutex);
pthread_mutex_unlock(&eh.eMutex);

DWORD EventDWord;
DWORD RxBytes;
DWORD TxBytes;
DWORD Status;
FT_GetStatus(ftHandle,&RxBytes,&TxBytes,&EventDWord);
if (EventDWord & FT_EVENT_MODEM_STATUS) {
    // modem status event detected, so get current modem status
    FT_GetModemStatus(ftHandle,&Status);
    if (Status & 0x00000010) {
          // CTS is high
    }
    else {
          // CTS is low
    }
    if (Status & 0x00000020) {
          // DSR is high
    }
    else {
          // DSR is low
    }
}
if (RxBytes > 0) {
    // call FT_Read() to get received data from device
}

FT_Close(ftHandle);

My code is c# using the d2xx driver, but I hope it helps. You have to create an EVENT_HANDLE for each FTDI device you open. Create the EventHandle when you open the device and destroy it when you close it. In the meanwile listen to events.

A global handle, shared between different devices, would have the effect of mixing up event notification from the devices. Not so good.

    public FTDISerialPortDevice(string serialNumber)
    {
        _serialNumber = serialNumber
        _ftdi = new FTDI(); // This is the ftdi device
        _bytesReceivedEvent = new AutoResetEvent(false);
    }
    
    public void Open()
    {
        if (_ftdi.IsOpen)
            throw new InvalidOperationException($"Access to the device '{_serialNumber}' is denied.");
    
        if (_ftdi.OpenBySerialNumber(_serialNumber ) != FTDI.FT_STATUS.FT_OK)
            throw new InvalidOperationException($"Access to the device '{_serialNumber }' is denied.");
    
         // Do device configuration stuff ....

        _ftdi.SetEventNotification(FTDI.FT_EVENTS.FT_EVENT_RXCHAR, _bytesReceivedEvent);
    
    }


    public int Receive(byte[] readBuffer, int offset)
    {
       // listen to event and do reads
    }