signals

来源： https://stackoverflow.com/questions/28082302/signal-sigterm-handling-of-multi-thread-process-under-linux

问题 I'm working on a server code that uses fork() and exec to create child processes. The PID of the child is registered when fork() succeeds and cleaned up when the CHILD signal has been caught. If the server needs to stop, all programs are killed, eventually with a KILL signal. Now, this works by means of iterating through all registered PIDs and waiting for the CHILD signal handler to remove the PIDs. This will fail if child program did not exit properly. Therefore I want to use kill in

问题 I'm working on a server code that uses fork() and exec to create child processes. The PID of the child is registered when fork() succeeds and cleaned up when the CHILD signal has been caught. If the server needs to stop, all programs are killed, eventually with a KILL signal. Now, this works by means of iterating through all registered PIDs and waiting for the CHILD signal handler to remove the PIDs. This will fail if child program did not exit properly. Therefore I want to use kill in

问题 I would like to open a window when I click on a QSpinBox . The problem is that there is no such signal "clicked" for this widget. Does someone has an idea how to do that? 回答1: A QSpinBox is just a QLineEdit with two buttons, input validation and event handling. It doesn't have clicked signal because it's supposed to handle the mouse even itself. The problem is that even making a custom widget derived from QSpinBox won't be enough since it doesn't receive the mouse events itself, they are

问题 I would like to open a window when I click on a QSpinBox . The problem is that there is no such signal "clicked" for this widget. Does someone has an idea how to do that? 回答1: A QSpinBox is just a QLineEdit with two buttons, input validation and event handling. It doesn't have clicked signal because it's supposed to handle the mouse even itself. The problem is that even making a custom widget derived from QSpinBox won't be enough since it doesn't receive the mouse events itself, they are

问题 I have been trying to do real-time audio signal processing using 'pyAudio' module in python. What I did was a simple case of reading audio data from microphone and play it via headphones. I tried with the following code(both Python and Cython versions). Thought it works but unfortunately it is stalls and not smooth enough. How can I improve the code so that it will run smoothly. My PC is i7, 8GB RAM. Python Version import pyaudio import numpy as np RATE = 16000 CHUNK = 256 p = pyaudio.PyAudio

问题 following example in this doc found on sourceforge I faced an error. from PyQt5.QtCore import pyqtSignal, pyqtSlot def setSignal(): signal = pyqtSignal() signal.connect(self.myAction) @QtCore.pyqtSlot() def myAction(): print("signal triggered") results in AttributeError: 'PyQt5.QtCore.pyqtSignal' object has no attribute 'connect' 回答1: As mentioned in the docs you linked, a signal needs to be defined on class level: class Foo(QObject): signal = pyqtSignal() def connectSignal(): self.signal

问题 To speed up Lambda execution, I am trying to move some parts of my Python code outside the handler function As per Lambda's documentation: After a Lambda function is executed, AWS Lambda maintains the Execution Context for some time in anticipation of another Lambda function invocation. In effect, the service freezes the Execution Context after a Lambda function completes, and thaws the context for reuse, if AWS Lambda chooses to reuse the context when the Lambda function is invoked again.

问题 Given a signal connected from the user to a callback function, the gtk_main thread sleeps until the signal is emitted. I searched for details on how or when it is emitted, but couldn't find any info that I don't know. More specifically is it emitted asynchronously so that I can invoke the signal in the middle of some function or it waits for the particular function to return first? Emitting the "switch-page" signal (for example with gtk_notebook_remove_page() ) from within GThread may have

问题 Given a signal connected from the user to a callback function, the gtk_main thread sleeps until the signal is emitted. I searched for details on how or when it is emitted, but couldn't find any info that I don't know. More specifically is it emitted asynchronously so that I can invoke the signal in the middle of some function or it waits for the particular function to return first? Emitting the "switch-page" signal (for example with gtk_notebook_remove_page() ) from within GThread may have