all Python 3Exceptionsexception

BaseException

built-in exceptions

The root of the exception hierarchy; catches everything, including SystemExit/KeyboardInterrupt.

Syntax

raise BaseException

What separates it from Exception is exactly the set of "stop the program" signals: SystemExit, KeyboardInterrupt and GeneratorExit inherit from BaseException directly. That is why except BaseException — and its twin, a bare except: — swallows Ctrl+C and sys.exit(), leaving the process unable to quit. If you do catch it for cleanup, end the handler with a bare raise.

Examples

try:
    raise BaseException
except BaseException as e:
    print(type(e).__name__)   # → BaseException

See also

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