QProcess exit normally

Question

I'm using python with qt and i cannot find out a way to fire a signal when Qprocess exit normally, According to Pyqt documentation finished() signal can take 2 arguments exitCode and exitStatus

This is what Pyqt documentation says about finished() signal

http://pyqt.sourceforge.net/Docs/PyQt4/qprocess.html#finished

void finished (int, ::QProcess::ExitStatus)

This is the default overload of this signal.

This signal is emitted when the process finishes. exitCode is the exit code of the process, and exitStatus is the exit status. After the process has finished, the buffers in QProcess are still intact. You can still read any data that the process may have written before it finished.

QProcess.ExitStatus

This enum describes the different exit statuses of QProcess.

Constant..................Value.........Description

QProcess.NormalExit....... 0.......The process exited normally.

QProcess.CrashExit........ 1.......The process crashed.

I tried to use this syntax but it did't work

self.process.finished(0,QProcess_ExitStatus=0).connect(self.status)

Remark:

Status is just as symbol for any slot (any action ) not something specific

Update:

To get a sense of the problem I've more than one process (Think of it as queue) i need python to execute the first process and only move to the next one if the previous process exits normally not forced to exit using kill() or terminate()

Thanks in advance

self.process.finished[int, QProcess.ExitStatus].connect(self.status) or just self.process.finished.connect(self.status) (which gets the default). — ekhumoro
Thanks this syntax was helpful i used self.process = QtCore.QProcess(self) self.process.finished[int,self.process.ExitStatus].connect(status) and fixed the problem but still one thing i can't figure it out ,why python understand this syntax in such way and i didn't gave it any value for ExitStatus to it him know whether i need to execute slot for NormalExit or CrashExit — Mohamed sayed
You don't need to do that: just use self.process.finished.connect(self.status), and it will do the right thing. The QProcess will automatically send the correct exit code and status when it emits the signal. So you just need to connect finished to a slot that takes two arguments, and then check the value of the arguments to decide what your code should do next. — ekhumoro

eyllanesc eyllanesc · Accepted Answer · 2018-12-20T23:42:18

You do not have to point to the symbol in the connection but in the slot with the help of pyqtSlot.

from PyQt4 import QtCore

class Helper(QtCore.QObject):
    def __init__(self, parent=None):
        super(Helper, self).__init__(parent)
        self.process = QtCore.QProcess(self)
        self.process.start("ping -c 4 google.com")
        self.process.finished.connect(self.status)

    @QtCore.pyqtSlot(int, QtCore.QProcess.ExitStatus)
    def status(self, exitCode, exitStatus):
        print(exitCode, exitStatus)
        QtCore.QCoreApplication.quit()

if __name__ == '__main__':
    import sys
    app = QtCore.QCoreApplication(sys.argv)
    h = Helper()
    sys.exit(app.exec_())

Update:

from PyQt4 import QtCore

class Helper(QtCore.QObject):
    def __init__(self, parent=None):
        super(Helper, self).__init__(parent)
        self.process = QtCore.QProcess(self)
        self.process.start("ping -c 4 google.com")
        self.process.finished.connect(self.on_finished)

    @QtCore.pyqtSlot(int, QtCore.QProcess.ExitStatus)
    def on_finished(self, exitCode, exitStatus):
        if exitStatus == QtCore.QProcess.NormalExit:
            self.status()

    def status(self):
        print("status")

QProcess exit normally

1 Answers