PYQT4 - Trying to pass a list to QProcess

[cminogue15]

I have Form A which starts a QProcess B (matplotlib widget).
When events come into Form A, I need to pass a list of data over the the
QProcess B. I am assuming I can do this using signal/slots.

Is this possible?

Code in Form A:

# define signal to emit
       PressureDataReady = QtCore.pyqtSignal()
 
  #  starts process
      self.qPSCGraph = QProcess()
      self.qPSCGraph.setProcessChannelMode(QProcess.SeparateChannels);   
      self.qPSCGraph.start('python', ['SmartCableGraphsPressureSensorData.py'])
      self.qPSCGraph.finished.connect(self.PSCGraphFinished)
 
    Method xyz(self):
        self.emit(QtCore.SIGNAL("PressureDataReady(PyQt_PyObject)"), pressureList)

# define signal to emit
       PressureDataReady = QtCore.pyqtSignal()

  #  starts process
      self.qPSCGraph = QProcess()
      self.qPSCGraph.setProcessChannelMode(QProcess.SeparateChannels);   
      self.qPSCGraph.start('python', ['SmartCableGraphsPressureSensorData.py'])
      self.qPSCGraph.finished.connect(self.PSCGraphFinished)

    Method xyz(self):
        self.emit(QtCore.SIGNAL("PressureDataReady(PyQt_PyObject)"), pressureList)

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Code In Form B:
???? not sure what is needed to receive signal and call method

self.connect(self.qPSCGraph, QtCore.SIGNAL("PressureDataReady(PyQt_PyObject)"), ??????, 0)

self.connect(self.qPSCGraph, QtCore.SIGNAL("PressureDataReady(PyQt_PyObject)"), ??????, 0)

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any example to point out the correct directions would be appreciated.

Chris

[jefftee]

To my knowledge, you cannot use Qt SIGNALS and SLOTS signals across separate processes.

A few other approaches you might consider based on your platform:

• Write to the stdin of your QProcess, read from stderr/stdout of your QProcess, etc.
• Use a database to insert work to do into a table from your main program and your QProcess checks for new work using a timer, etc.
• Use some type of message queueing system to publish/consume messages between processes
• Use the Qt DBUS stuff

Edit: A quick google found this page as well.

Hope that helps.