Python Interrupted Error
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This module never needs to be imported explicitly: the exceptions are provided in the built-in namespace as well as the exceptions module. For class exceptions, in a try statement with an python filenotfounderror except clause that mentions a particular class, that clause also handles any
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exception classes derived from that class (but not exception classes from which it is derived). Two exception classes that are
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not related via subclassing are never equivalent, even if they have the same name. The built-in exceptions listed below can be generated by the interpreter or built-in functions. Except where mentioned, they have
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an "associated value" indicating the detailed cause of the error. This may be a string or a tuple containing several items of information (e.g., an error code and a string explaining the code). The associated value is the second argument to the raise statement. If the exception class is derived from the standard root class BaseException, the associated value is present as the exception instance's python exception class methods args attribute. User code can raise built-in exceptions. This can be used to test an exception handler or to report an error condition "just like" the situation in which the interpreter raises the same exception; but beware that there is nothing to prevent user code from raising an inappropriate error. The built-in exception classes can be subclassed to define new exceptions; programmers are encouraged to derive new exceptions from the Exception class or one of its subclasses, and not from BaseException. More information on defining exceptions is available in the Python Tutorial under User-defined Exceptions. The following exceptions are only used as base classes for other exceptions. exception BaseException¶ The base class for all built-in exceptions. It is not meant to be directly inherited by user-defined classes (for that, use Exception). If str() or unicode() is called on an instance of this class, the representation of the argument(s) to the instance are returned, or the empty string when there were no arguments. New in version 2.5. args¶ The tuple of arguments given to the exception constructor. Some built-in exceptions (like IOError) expect a certain number of arguments and assign a spe
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies of this site About Us Learn more about Stack Overflow the company Business Learn python errno more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags python attributeerror object has no attribute Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, python 3 exceptions helping each other. Join them; it only takes a minute: Sign up What is the proper way to handle (in python) IOError: [Errno 4] Interrupted system call, raised by multiprocessing.Queue.get up vote 9 down vote favorite When I https://docs.python.org/2/library/exceptions.html use multiprocessing.Queue.get I sometimes get an exception due to EINTR. I know definitely that sometimes this happens for no good reason (I open another pane in a tmux buffr), and in such a case I would want to continue working and retry the operation. I can imagine that in some other cases The error would be due to a good reason and I should stop running or fix some error. How can I distinguish the two? http://stackoverflow.com/questions/14136195/what-is-the-proper-way-to-handle-in-python-ioerror-errno-4-interrupted-syst Thanks in advance python error-handling queue multiprocessing ioerror share|improve this question asked Jan 3 '13 at 9:36 Shwouchk 9028 you should make sure the queue is not empty before get: if not queue.empty(): queue.get() –Inbar Rose Jan 3 '13 at 9:39 I believe that if the queue is empty, it will just block the call. Won't it? In any I don't think this is the cause of the error. –Shwouchk Jan 3 '13 at 10:26 add a comment| 2 Answers 2 active oldest votes up vote 11 down vote accepted The EINTR error can be returned from many system calls when the application receives a signal while waiting for other input. Typically these signals can be quite benign and already handled by Python, but the underlying system call still ends up being interrupted. When doing C/C++ coding this is one reason why you can't entirely rely on functions like sleep(). The Python libraries sometimes handle this error code internally, but obviously in this case they're not. You might be interested to read this thread which discusses this problem. The general approach to EINTR is to simply handle the error and retry the operation again - this should be a safe thing to do with the get() method on the queue. Something like this could be used, passing the queue as a param
here for a quick overview of the site Help Center Detailed answers to any questions you might have Meta Discuss the workings and policies http://stackoverflow.com/questions/3016369/catching-blocking-sigint-during-system-call of this site About Us Learn more about Stack Overflow the company http://effbot.org/zone/stupid-exceptions-keyboardinterrupt.htm Business Learn more about hiring developers or posting ads with us Stack Overflow Questions Jobs Documentation Tags Users Badges Ask Question x Dismiss Join the Stack Overflow Community Stack Overflow is a community of 6.2 million programmers, just like you, helping each other. Join them; it only takes a python exception minute: Sign up Catching / blocking SIGINT during system call up vote 7 down vote favorite 2 I've written a web crawler that I'd like to be able to stop via the keyboard. I don't want the program to die when I interrupt it; it needs to flush its data to disk first. I also don't want to catch KeyboardInterruptedException, because the python interrupted error persistent data could be in an inconsistent state. My current solution is to define a signal handler that catches SIGINT and sets a flag; each iteration of the main loop checks this flag before processing the next url. However, I've found that if the system happens to be executing socket.recv() when I send the interrupt, I get this: ^C Interrupted; stopping... // indicates my interrupt handler ran Traceback (most recent call last): File "crawler_test.py", line 154, in
is, like all other exceptions, caught by a "catch-all" try-except statement. try: # do something except: # you'll end up here if something goes wrong, # or if the user presses control-cFor example, if your program contains code like the following, your users may find that pressing Control-C is a great way to mess up their database, but a really lousy way to stop the program: for record in database: try: process(record) if changed: update(record) except: # report error and proceedTo solve the exception problem, add a separate except-clause that catches the KeyboardInterrupt exception, and raises it again: for record in database: try: process(record) if changed: update(record) except KeyboardInterrupt: raise except: # report error and proceedor, even better: for record in database: try: process(record) if changed: update(record) except (KeyboardInterrupt, SystemExit): raise except: # report error and proceedBy looking for SystemExit as well, calling sys.exit() in the processing or update code will actually stop the program.Note that if the update process isn't an atomic operation in itself, it's also a good idea to use database transactions, and roll back when something goes wrong: for record in database: begin() try: process(record) if changed: update(record) except (KeyboardInterrupt, SystemExit): rollback() raise except: rollback() # report error and proceed else: commit()::: effbot.org::: zone ::: rendered by a django application. hosted by webfaction.