Proximity-card reader: no data when app window out of focus

Applications Programming
1

Hello. I can't get it work :frowning:
My application receives data from em-marin reader only being active. Switching to another app makes the port become silent.
MarinReader works in another thread.
Port reading is going while the app is inactive (tested).
Env: Ubuntu 9.04, Gnome, Qt (i've tryed pure open and fopen - the same result)
Please, help anybody!

bool MarinReader::read_port(QFile* file)
{
	char first_char = '\0';
	file->getChar(&first_char);
	if (first_char == ':')
	{
		QByteArray bres = file->readAll();
		QString s(bres);
		s.resize(10);
		emit CardProcessed(s);
	}
	tcflush(file->handle(), TCIOFLUSH);
	return true;
}

void MarinReader::run()
{
	emit Message("opening port " + port_name);
	struct termios Posix_CommConfig;
	QFile* Posix_File = new QFile(port_name);
	if (!Posix_File->open(QIODevice::ReadOnly))
	{
		emit Error("open file error"); exit(-1); return;
	}
/* doesn't solve the problem
	struct flock fl;
	fl.l_type   = F_RDLCK;
	fl.l_whence = SEEK_SET;
	fl.l_start  = 0; 
	fl.l_len    = 0; 
	fl.l_pid    = getpid(); 
	fcntl(Posix_File->handle(), F_SETLK, &fl); 
*/
	tcgetattr(Posix_File->handle(), &Posix_CommConfig);
	Posix_CommConfig.c_cflag |= CREAD|CLOCAL;
	Posix_CommConfig.c_lflag &= (~(ICANON|ECHO|ECHOE|ECHOK|ECHONL|ISIG));
	Posix_CommConfig.c_iflag &= (~(INPCK|IGNPAR|PARMRK|ISTRIP|ICRNL|IXANY));
	Posix_CommConfig.c_oflag &= (~OPOST);
	Posix_CommConfig.c_cc[VMIN] = 0;
	Posix_CommConfig.c_cc[VINTR] = _POSIX_VDISABLE;
	Posix_CommConfig.c_cc[VQUIT] = _POSIX_VDISABLE;
	Posix_CommConfig.c_cc[VSTART] = _POSIX_VDISABLE;
	Posix_CommConfig.c_cc[VSTOP] = _POSIX_VDISABLE;
	Posix_CommConfig.c_cc[VSUSP] = _POSIX_VDISABLE;
	//speed
	cfsetispeed(&Posix_CommConfig, B9600);
	cfsetospeed(&Posix_CommConfig, B9600);
	//data bits
	Posix_CommConfig.c_cflag&=(~CSIZE);
	Posix_CommConfig.c_cflag|=CS8;
	//parity
	Posix_CommConfig.c_cflag&=(~PARENB);
	//stop bits
	Posix_CommConfig.c_cflag&=(~CSTOPB);
	//flow control
	Posix_CommConfig.c_cflag&=(~CRTSCTS);
	Posix_CommConfig.c_iflag&=(~(IXON|IXOFF|IXANY));
	//timeout
	Posix_CommConfig.c_cc[VTIME] = 1;
	if (tcsetattr(Posix_File->handle(), TCSAFLUSH, &Posix_CommConfig) == -1)
	{
		emit Error("tcsetattr error"); exit(-1); return;
	}
	is_open = true;
	emit Message("port opened successfully");
	do
	{
		if (!read_port(Posix_File)) break;
	}
	while (!needClose);
	needClose = false;
	//fl.l_type = F_UNLCK;
	//fcntl(Posix_File->handle(), F_SETLK, &fl); 
	Posix_File->close();
	delete Posix_File;
	emit Message("port closed");
	is_open = false;
}
2

Can you not make the reader a separate process - a daemon - that raises a signal or otherwise sends something to your windowing code? An unblocked signal is never ignored, for example.

Regardless of focus.

3

With the following modification my windowing code gets all the counted signals:

bool MarinReader::read_port(QFile* file)
{
	static int i = 0;
	emit Message("debug message #" + QString::number(i++));
	char first_char = '\0';
	file->getChar(&first_char);
	if (first_char == ':')
	{
		QByteArray bres = file->readAll();
		QString s(bres);
		s.resize(10);
		emit CardProcessed(s);
	}
	tcflush(file->handle(), TCIOFLUSH);
	return true;
}

Signals CardProcessed and Message are identical, and the destination slots are in the same thread of main window (I can process these signals with the same slot).