multiple process ID while QProcess start() function

[arunanncyda]

Hi

Im my program, activating the the GPRS using Qprocess start function, while executing this program will activate the GPRS. But the application is creating two more process PID with same application name & that two process will not be terminating. kindly help me how to solve this problem.

void GPRSCall::activateGPRS() {
	QProcess *activateProcess;
	activateProcess = new QProcess();
	connect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
	activateProcess->start("pppd call gprs-airtel",QIODevice::ReadOnly);
}
 
void GPRSCall::readGPRS()
{
    str = activateProcess->readAllStandardOutput();
    qDebug() << str;
    if(str.contains("local  IP address")) {
        QString ipAddress=getip("ppp0");
        emit gprsResponse(tr("GPRS Activated Successfully<br>IP : ")+ipAddress);
        activateProcess->disconnect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
    } else if(str.contains("script failed") || str.contains("Serial link disconnected")) {
        emit gprsResponse(tr("GPRS Activation Failed"));
        activateProcess->disconnect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
    } else if(str.contains("ttyUSB0 is locked")) {
            emit  gprsResponse(tr("GPRS Activation Failed"));
    }
    else if(str.contains("Modem hangup")) {
        emit gprsResponse(tr("Modem Hangup"));
        activateProcess->disconnect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
    }
}
 
/*Obtains the IP Address from the conncted network interrface*/
QString GPRSCall::getip(QString dev)
{
    QNetworkInterface iface = QNetworkInterface::interfaceFromName(dev);
    QList<QNetworkAddressEntry> ipList = iface.addressEntries();
    for (int i = 0; i < ipList.size(); ++i)
        return ipList.at(i).ip().toString();
    return "No Link";
}
 
 
/********************GPRS Deactivation********************/
/*GPRS Disconnect Script is called from a process in ReadOnly Mode*/
void GPRSCall::deactivateGPRS()
{
    connect(deactivateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(closeGPRS()));
        deactivateProcess->start("sh /opt/Resources/gprs_disconnect.sh",QIODevice::ReadOnly);
        delay(1);///add Stopping PPP interface  to readyreadstandarouuput method...
}
 
/***************Read Deactivation Script Output***************/
/*Invoked form Disconnect Script to read its output and display
  the status to the user*/
void GPRSCall::closeGPRS()
{
    str = deactivateProcess->readAllStandardOutput();
    if(str.contains("Stopping PPP interface ")) {
        emit gprsResponse(tr("GPRS Deactivation Success"));
        deactivateProcess->disconnect(deactivateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(closeGPRS()));
    }
}

void GPRSCall::activateGPRS() {
	QProcess *activateProcess;
	activateProcess = new QProcess();
	connect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
	activateProcess->start("pppd call gprs-airtel",QIODevice::ReadOnly);
}

void GPRSCall::readGPRS()
{
    str = activateProcess->readAllStandardOutput();
    qDebug() << str;
    if(str.contains("local  IP address")) {
        QString ipAddress=getip("ppp0");
        emit gprsResponse(tr("GPRS Activated Successfully<br>IP : ")+ipAddress);
        activateProcess->disconnect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
    } else if(str.contains("script failed") || str.contains("Serial link disconnected")) {
        emit gprsResponse(tr("GPRS Activation Failed"));
        activateProcess->disconnect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
    } else if(str.contains("ttyUSB0 is locked")) {
            emit  gprsResponse(tr("GPRS Activation Failed"));
    }
    else if(str.contains("Modem hangup")) {
        emit gprsResponse(tr("Modem Hangup"));
        activateProcess->disconnect(activateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(readGPRS()));
    }
}

/*Obtains the IP Address from the conncted network interrface*/
QString GPRSCall::getip(QString dev)
{
    QNetworkInterface iface = QNetworkInterface::interfaceFromName(dev);
    QList<QNetworkAddressEntry> ipList = iface.addressEntries();
    for (int i = 0; i < ipList.size(); ++i)
        return ipList.at(i).ip().toString();
    return "No Link";
}


/********************GPRS Deactivation********************/
/*GPRS Disconnect Script is called from a process in ReadOnly Mode*/
void GPRSCall::deactivateGPRS()
{
    connect(deactivateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(closeGPRS()));
        deactivateProcess->start("sh /opt/Resources/gprs_disconnect.sh",QIODevice::ReadOnly);
        delay(1);///add Stopping PPP interface  to readyreadstandarouuput method...
}

/***************Read Deactivation Script Output***************/
/*Invoked form Disconnect Script to read its output and display
  the status to the user*/
void GPRSCall::closeGPRS()
{
    str = deactivateProcess->readAllStandardOutput();
    if(str.contains("Stopping PPP interface ")) {
        emit gprsResponse(tr("GPRS Deactivation Success"));
        deactivateProcess->disconnect(deactivateProcess,SIGNAL(readyReadStandardOutput()),this,SLOT(closeGPRS()));
    }
}

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Note : USing QT 4.8.1 version & Linux 2.6.36.4 armv5tejl GNU/Linux

[anda_skoa]

That should actually crash.

activateGPRS() is storing the QProcess pointer in a local variable, readGPRS() is accessing a member variable.

Cheers,
_

[arunanncyda]

Hi,
Thank for your reply, I extended scope of QProcess by declaring it in header file. Now also I am getting same problem.

QT Code
void GPRSCall::activateGPRS() {
// QProcess *activateProcess; // Moved to Header file
// activateProcess = new QProcess(); // Moved to constructor.
connect(activateProcess,SIGNAL(readyReadStandardOu tput()),this,SLOT(readGPRS()));
activateProcess->start("pppd call gprs-airtel",QIODevice::ReadOnly);
}

[arunanncyda]

Hi,
Thank for your reply, I extended scope of QProcess by declaring it in header file. Now also I am getting same problem.

QT Code
void GPRSCall::activateGPRS() {
// QProcess *activateProcess; // Moved to Header file
// activateProcess = new QProcess(); // Moved to constructor.
connect(activateProcess,SIGNAL(readyReadStandardOu tput()),this,SLOT(readGPRS()));
activateProcess->start("pppd call gprs-airtel",QIODevice::ReadOnly);
}

[^NyAw^]

Hi,

Use a debugger and check how many times "activateGPRS()" is called.