Ctrl-C不适用于PyQ

Question

为什么不Ctrl+C来中断使用PyQt的Python程序？我想调试它，并获得堆栈跟踪，由于某种原因，这是更难做到比用C++！

Answer 1

我同意尼尔G的观点，并补充如下：

如果不调用QApplication.exec（）来启动事件循环，而是在一个交互式python shell（使用python-i）中执行程序，那么pyqt将在交互式提示等待时自动处理事件，Ctrl-C应再次按预期操作。这是因为Qt事件循环将与python解释器共享时间，而不是独占运行，从而使解释器有机会捕获这些中断。

Answer 2

CTRL+C causes a signal to be sent to the process. Python catches the signal, and sets a global variable, something like CTRL_C_PRESSED = True. Then, whenever the Python interpreter gets to execute a new opcode, it sees the variable set and raises a KeybordInterrupt.

This means that CTRL+C works only if the Python interpreter is spinning. If the interpreter is executing an extension module written in C that executes a long-running operation, CTRL+C won't interrupt it, unless it explicitly "cooperates" with Python. Eg: time.sleep() is theoretically a blocking operation, but the implementation of that function "cooperates" with the Python interpreter to make CTRL+C work.

This is all by design: CTRL+C is meant to do a "clean abort"; this is why it gets turned into an exception by Python (so that the cleanups are executed during stack unwind), and its support by extension modules is sort of "opt-in". If you want to totally abort the process, without giving it a chance to cleanup, you can use CTRL+.

When Python calls QApplication::exec() (the C++ function), Qt doesn't know how to "cooperate" with Python for CTRL+C, and this is why it does not work. I don't think there's a good way to "make it work"; you may want to see if you can handle it through a global event filter. — Giovanni Bajo

把这个加到主程序中解决了这个问题。

import signal

signal.signal(signal.SIGINT, signal.SIG_DFL)

我不知道这和解释有什么关系。