Qt-interest Archive, December 2006
QFile::waitForReadyRead doesn't block?
Message 1 in thread
Hi,
I am developeing an application that must connect to a device through a
serial port. The protocol requires an escape sequence like a modem - a
1 second timeout, the string "+++" and a 1 second timeout - before
sending any command.
I made a working thread that communicate with the gui through a
queue/semaphore/mutex system.
This is the sendEscape function in the thread:
bool CFeeder::sendEscape()
{
QThread::sleep(1);
m_dev->write ("+++");
qDebug ("=> +++");
QThread::sleep(1);
bool b = m_dev->waitForReadyRead (1000); // Wait 1000ms for resp.
qDebug ("returned %d", b);
QString response = m_dev->readLine(); // ignore
qDebug ("<= %s", response.toLatin1().constData());
return true;
}
The problem is that the waitForReadyRead() always returns 0 - without
waiting the timeout .
What I am missing? m_dev is a QFile, which has been opened passing the
file descriptor to the /dev/ttyS0 device - because I must setup the
serial port with the termios.h tc{set,get}attr() functions.
What am I missing?
TIA
ing. Federico Fuga
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Message 2 in thread
I can confirm this problem. Same problem here!
ing. Federico Fuga wrote:
> Hi,
>
> I am developeing an application that must connect to a device through a
> serial port. The protocol requires an escape sequence like a modem - a
> 1 second timeout, the string "+++" and a 1 second timeout - before
> sending any command.
> I made a working thread that communicate with the gui through a
> queue/semaphore/mutex system.
> This is the sendEscape function in the thread:
>
> bool CFeeder::sendEscape()
> {
> QThread::sleep(1);
>
> m_dev->write ("+++");
> qDebug ("=> +++");
>
> QThread::sleep(1);
> bool b = m_dev->waitForReadyRead (1000); // Wait 1000ms for resp.
> qDebug ("returned %d", b);
> QString response = m_dev->readLine(); // ignore
> qDebug ("<= %s", response.toLatin1().constData());
> return true;
> }
>
> The problem is that the waitForReadyRead() always returns 0 - without
> waiting the timeout .
> What I am missing? m_dev is a QFile, which has been opened passing the
> file descriptor to the /dev/ttyS0 device - because I must setup the
> serial port with the termios.h tc{set,get}attr() functions.
> What am I missing?
>
> TIA
>
> ing. Federico Fuga
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