Exception O S 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 python exceptions list module. For class exceptions, in a try statement with an except clause that mentions a particular class, that clause also handles any exception classes derived from that python exception message class (but not exception classes from which it is derived). Two exception classes that are not related via subclassing are never equivalent, even if they have the same
Python 3 Exceptions
name. The built-in exceptions listed below can be generated by the interpreter or built-in functions. Except where mentioned, they have 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 python exception class methods 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 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). 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Join them; it only takes a minute: Sign up Python - except (OSError, e) - No longer working in 3.3.3? up vote 1 down vote favorite The following have https://docs.python.org/2/library/exceptions.html worked throughout Python 3.X and is not broke in 3.3.3, can't find what's changed in the docs. import os def pid_alive(pid): pid = int(pid) if pid < 0: return False try: os.kill(pid, 0) except (OSError, e): return e.errno == errno.EPERM else: return True Tried different variations of the except line, for instance except OSError as e: but then errno.EPERM breaks etc. Any quick pointers? python exception-handling python-3.3 share|improve this question edited Apr 14 '14 http://stackoverflow.com/questions/20517785/python-except-oserror-e-no-longer-working-in-3-3-3 at 22:52 Martijn Pieters♦ 500k7412981454 asked Dec 11 '13 at 11:23 Torxed 9,46354169 add a comment| 1 Answer 1 active oldest votes up vote 12 down vote accepted The expression except (OSError, e) never worked in Python, not in the way you think it works. That expresion catches two types of exception; OSError or whatever the global e refers to. Your code breaks when there is no global name e. The correct expression for Python 3 and Python 2.6 and newer is: except OSError as e: Python 2 also supports the syntax: except OSError, e: without parenthesis, or: except (OSError, ValueError), e: to catch more than one type. The syntax was very confusing, as you yourself discovered here. The change was added in Python 2.6 and up, see PEP 3110 - Catching Exceptions in Python 3000 and the Exception-handling changes section of the 2.6 What's New document. As for an exception for errno.EPERM; you didn't import errno, so that is a NameError as well. share|improve this answer edited Dec 11 '13 at 11:30 answered Dec 11 '13 at 11:24 Martijn Pieters♦ 500k7412981454 Missed import errno as well, that was the root cause and again a stupid question on my part which i spent a few hours on.. What's the difference between (OSError, e) and X a Exception StandardError ArithmeticError LookupError EnvironmentError Raised Exceptions AssertionError AttributeError EOFError FloatingPointError GeneratorExit IOError ImportError IndexError KeyError KeyboardInterrupt https://pymotw.com/2/exceptions/ MemoryError NameError NotImplementedError OSError OverflowError ReferenceError RuntimeError StopIteration SyntaxError SystemError SystemExit TypeError UnboundLocalError UnicodeError ValueError ZeroDivisionError Warning Categories Navigation Table of Contents Previous: Built-in Objects Next: String Services https://bytes.com/topic/python/answers/35950-getting-errno-oserror-exception This Page Show Source Examples The output from all the example programs from PyMOTW has been generated with Python 2.7.8, unless otherwise noted. Some of the features python exception described here may not be available in earlier versions of Python. If you are looking for examples that work under Python 3, please refer to the PyMOTW-3 section of the site. Navigation index modules | next | previous | PyMOTW » Built-in Objects » exceptions - Built-in error classes¶ Purpose:The exceptions module defines the built-in exception o s errors used throughout the standard library and by the interpreter. Available In:1.5 and later Description¶ In the past, Python has supported simple string messages as exceptions as well as classes. Since 1.5, all of the standard library modules use classes for exceptions. Starting with Python 2.5, string exceptions result in a DeprecationWarning, and support for string exceptions will be removed in the future. Base Classes¶ The exception classes are defined in a hierarchy, described in the standard library documentation. In addition to the obvious organizational benefits, exception inheritance is useful because related exceptions can be caught by catching their base class. In most cases, these base classes are not intended to be raised directly. BaseException¶ Base class for all exceptions. Implements logic for creating a string representation of the exception using str() from the arguments passed to the constructor. Exception¶ Base class for exceptions that do not result in quitting the running application. All user-defined exceptions should use Exception as a base class. Sta question and get tips & solutions from a community of 418,548 IT Pros & Developers. It's quick & easy. getting errno from OSError exception? P: n/a Mark Harrison Can somebody loan me a clue as to how to check the errno on an OSError, as described below? try: os.makedirs(d) except OSError: # if errno == 17 then silently ignore the error because the # other process won the race condition and created the directory # otherwise, allow the exception to percolate up the call stack # and be caught by the standard error reporter Many TIA! Mark -- Mark Harrison Pixar Animation Studios Jul 18 '05 #1 Post Reply Share this Question 1 Reply P: n/a George Yoshida Mark Harrison wrote: Can somebody loan me a clue as to how to check the errno on an OSError, as described below? try: os.makedirs(d) except OSError: # if errno == 17 then silently ignore the error because the # other process won the race condition and created the directory # otherwise, allow the exception to percolate up the call stack # and be caught by the standard error reporter What about this? try: os.makedirs(d) except OSError, e: if e.errno == 17: do_something - george Jul 18 '05 #2 This discussion thread is closed Start new discussion Replies have been disabled for this discussion. Similar topics Pyserial not getting response every time, input/output errors Trouble with subprocess.call(...) and zsh script (OSError: [Errno 8] Exec format error) Built-in Exceptions - How to Find Out Possible Errno's 206 The filename or extension is too long / OSError: [Errno 38] Filenametoo long Oserror: [Errno 20] os.remove OSError: [Errno 13] Permission denied Occasional OSError: [Errno 13] Permission denied on Windows [Errno 18] Invalid cross-device link using os.rename Getting the Directory/Path details Browse more Python Questions on Bytes Question stats viewed: 5004 replies: 1 date asked: Jul 18 '05 Follow this discussion BYTES.COM © 2016 Formerly "TheScripts.com" from 2005-2008 About Bytes | Advertise on Bytes | Contact Us Sitemap | Python Answers Sitemap | Python Insights Sitemap FPython Filenotfounderror
Python Exception Stack Trace