c++ - 嵌套的DirectConnection信号导致段错误

这是我的unanswered question here的后续。如下所示，该代码完全与segfault崩溃(将其复制/粘贴到您的系统中并运行它)。当我从一个或两个信号构造函数调用中删除type=QtCore.Qt.DirectConnection(从而改为使用QtCore.Qt.AutoConnection)时，所有内容均按应有的方式运行:出现一个小部件，显示五个进度条填满，然后以无穷循环的方式清空。

from PySide import QtCore, QtGui
import time

class Worker(QtCore.QThread):
    sig_worker_update_progress = QtCore.Signal(int, int)

    def __init__(self, thread_id, *args, **kwargs):
        super(Worker, self).__init__(*args, **kwargs)
        self.thread_id = thread_id
        self.stop_requested = False

    def slot_interrupt(self):
        self.stop_requested = True

    def run(self):
        progress = 0
        while(True):
            self.sig_worker_update_progress.emit(self.thread_id, progress % 100)
            progress += 1
            if self.stop_requested:
                break
            else:
                time.sleep(0.1)


class Controller(QtCore.QObject):
    sig_controller_update_progress = QtCore.Signal(int, int)

    def __init__(self, num_workers, *args, **kwargs):
        super(Controller, self).__init__(*args, **kwargs)

        self.workers = []
        for i in range(num_workers):
            self.workers.append(Worker(i))
            self.workers[i].sig_worker_update_progress.connect(
                self.slot_worker_update_progress,
                type=QtCore.Qt.DirectConnection)
        for worker in self.workers:
            worker.start()

    def slot_worker_update_progress(self, thread_id, progress):
        # Do
        # Stuff
        self.sig_controller_update_progress.emit(thread_id, progress)


class Monitor(QtGui.QWidget):
    def __init__(self, num_workers, *args, **kwargs):
        super(Monitor, self).__init__(*args, **kwargs)
        main_layout = QtGui.QVBoxLayout()
        self.setLayout(main_layout)
        self.progress_bars = []

        for _ in range(num_workers):
            progress_bar = QtGui.QProgressBar()
            main_layout.addWidget(progress_bar)
            self.progress_bars.append(progress_bar)

        self.controller  = Controller(num_workers)
        self.controller.sig_controller_update_progress.connect(
            self.slot_controller_update_progress,
            type=QtCore.Qt.DirectConnection)

    def slot_controller_update_progress(self, thread_id, progress):
        self.progress_bars[thread_id].setValue(progress)


if __name__ == "__main__":
    app = QtGui.QApplication([])
    monitor = Monitor(5)
    monitor.show()
    app.exec_()

为什么使用两个嵌套的DirectConnection信号会导致段错误？如果Qt不希望您这样做，为什么没有给出更多有用的错误？

我正在使用包装Qt 4.8框架的PySide v1.2.2。

最佳答案

我找到了令人满意的解释here。显然，发出DirectConnection类型的信号等效于直接函数调用。因此，当两个信号都经过Worker编码时，GUI毕竟是在DirectConnect线程上更新的。如我的other question所述，不允许线程更改GUI。问题不在于本身嵌套DirectConnection。

关于c++ - 嵌套的DirectConnection信号导致段错误，我们在Stack Overflow上找到一个类似的问题：https://stackoverflow.com/questions/27690865/