def _termination_callback(self, returncode):
        """
        Called when the process has stopped.

        :param returncode: Process returncode
        """
        if self._started:
            log.info("VPCS process has stopped, return code: %d", returncode)
            self._started = False
            self.status = "stopped"
            self._process = None
            if returncode != 0:
                self.project.emit("log.error", {"message": "VPCS process has stopped, return code: {}\n{}".format(returncode, self.read_vpcs_stdout())})
Called when the process has stopped.

        :param returncode: Process returncode