Python Set Error Code
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Python Get Exit Code
vote 77 down vote favorite 12 I got a message saying script xyz.py returned exit code 0. What does this mean? What do the exit codes in Python mean? How many are there? Which ones are important? python exit-code share|improve this question edited Oct 15 '12 at 9:11 Teun Zengerink 2,73941929 asked Nov 12 '08 at 20:43 sundeep 71831120 Where are you seeing this python script return value to shell message? –Jeremy Cantrell Nov 12 '08 at 21:15 @Jeremy At the bottom of PythonWin. –sundeep Nov 12 '08 at 21:19 add a comment| 9 Answers 9 active oldest votes up vote 92 down vote accepted What you're looking for in the script is calls to sys.exit(). The argument to that method is returned to the environment as the exit code. It's fairly likely that the script is never calling the exit method, and that 0 is the default exit code. share|improve this answer edited May 20 '15 at 7:31 Teun Zengerink 2,73941929 answered Nov 12 '08 at 20:50 Dave Costa 33.1k43853 6 Not sure at all. In Unix/Linux, the standard is: exit 0 in the case everything was ok. Type a command, then echo $?: if you read 0, it returned without an error. The idea is to have standard tests. If the code xyz.py did not encounter any error, it SHOULD return 0! –Bruno von Paris Oct 15 '12 at 9:20 add a comment| up vote 43 down vote From the documentation for sys.exit: The optional argument arg can be an integer giving the exit status (defaulting to zero), or an
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Python Exit Code 255
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Python Check Exit Code
Difference between exit(0) and exit(1) in Python up vote 52 down vote favorite 7 What's the difference between exit(0) and exit(1) in Python? I tried looking around but didn't find a specific question on these lines. If it's already been answered, http://stackoverflow.com/questions/285289/exit-codes-in-python a link would be sufficient. python exit-code share|improve this question edited Sep 18 '15 at 18:43 Kasper Souren 4,29332661 asked Feb 24 '12 at 5:49 KodeSeeker 1,79784577 3 Here's a link to exit() in the docs, which took me forever to find. –Ryne Everett Apr 4 '14 at 2:08 1 keep in mind: The site module (which is imported automatically during startup, except if the -S command-line option is given) adds several constants to the built-in namespace. They are useful for the http://stackoverflow.com/questions/9426045/difference-between-exit0-and-exit1-in-python interactive interpreter shell and should not be used in programs, instead, use sys.exit() –Udi May 7 '14 at 18:12 add a comment| 5 Answers 5 active oldest votes up vote 91 down vote accepted 0 and 1 are the exit codes. exit(0) means a clean exit without any errors / problems exit(1) means there was some issue / error / problem and that is why the program is exiting. This is not Python specific and is pretty common. A non-zero exit code is treated as an abnormal exit, and at times, the error code indicates what the problem was. A zero error code means a successful exit. This is useful for other programs, shell, caller etc. to know what happened with your program and proceed accordingly. share|improve this answer answered Feb 24 '12 at 5:50 manojlds 154k26280306 2 And what about exit(-1) ? –Faizan Apr 1 '14 at 10:46 5 @Faizan: The exit code is an 8-bit value on Unix. If you invoke exit(-1), the value is equivalent to exit(255) - the least significant 8 bits are relayed to the calling program (shell or whatever). –Jonathan Leffler Feb 6 '15 at 15:46 add a comment| up vote 9 down vote This determines the exit status of the program when it finishes running (generally, 0 for success and 1 for error). It is not unique to Python, and the exact effect depends on your operating system and how the program is called (though 99% of the time, if you
you have probably seen some. There are (at least) two distinguishable kinds of errors: syntax errors and exceptions. 8.1. Syntax Errors¶ Syntax errors, also known as parsing errors, are perhaps the most common kind of complaint you get https://docs.python.org/3/tutorial/errors.html while you are still learning Python: >>> while True print('Hello world') File "
is important to understand some of the basics of Python exception handling. It works somewhat like the POSIX errno variable: there is a global indicator (per thread) of the last error that occurred. Most C API functions don't clear this on success, but will set it to indicate the cause of the error on failure. Most C API functions also return an error indicator, usually NULL if they are supposed to return a pointer, or -1 if they return an integer (exception: the PyArg_*() functions return 1 for success and 0 for failure). Concretely, the error indicator consists of three object pointers: the exception's type, the exception's value, and the traceback object. Any of those pointers can be NULL if non-set (although some combinations are forbidden, for example you can't have a non-NULL traceback if the exception type is NULL). When a function must fail because some function it called failed, it generally doesn't set the error indicator; the function it called already set it. It is responsible for either handling the error and clearing the exception or returning after cleaning up any resources it holds (such as object references or memory allocations); it should not continue normally if it is not prepared to handle the error. If returning due to an error, it is important to indicate to the caller that an error has been set. If the error is not handled or carefully propagated, additional calls into the Python/C API may not behave as intended and may fail in mysterious ways. Note The error indicator is not the result of sys.exc_info(). The former corresponds to an exception that is not yet caught (and is therefore still propagating), while the latter returns an exception after it is caught (and has therefore stopped propagating). Printing and clearing