enable ctrl-c

ctrl_c.py

@@ -0,0 +1,40 @@
+import signal
+import socket
+from PyQt5.QtNetwork import QAbstractSocket
+
+
+def setup(app):
+    app.signalwatchdog = SignalWatchdog() # need to store to keep socket pair alive
+    signal.signal(signal.SIGINT, make_quit_handler(app))
+
+
+def make_quit_handler(app):
+    def handler(*args):
+        print() # make ^C appear on its own line
+        app.quit()
+    return handler
+
+
+
+class SignalWatchdog(QAbstractSocket):
+
+    def __init__(self):
+        """
+        Propagates system signals from Python to QEventLoop
+        adapted from https://stackoverflow.com/a/65802260/655404
+        """
+        super().__init__(QAbstractSocket.SctpSocket, None)
+
+        self.writer, self.reader = writer, reader = socket.socketpair()
+        writer.setblocking(False)
+
+        fd_writer = writer.fileno()
+        fd_reader = reader.fileno()
+
+        signal.set_wakeup_fd(fd_writer) # Python hook
+        self.setSocketDescriptor(fd_reader) # Qt hook
+
+        self.readyRead.connect(lambda: None) # dummy function call that lets the Python interpreter run
+
+
+

grum.py

@@ -4,9 +4,11 @@ import sys
 from PyQt5.QtWidgets import QApplication
 from mainwin import MainWindow
 from theme import theme
+import ctrl_c
 
 app = QApplication(sys.argv)
 theme(app)
+ctrl_c.setup(app)
 mw = MainWindow()
 mw.show()
 sys.exit(app.exec())