all Python 3signalfunction

signal.default_int_handler()

handlers

The default SIGINT handler: it raises KeyboardInterrupt. Reinstall it to restore the usual reaction to Ctrl+C.

Syntax

signal.signal(signal.SIGINT, signal.default_int_handler)

Restoring Ctrl+C with SIG_DFL is a common mistake: SIG_DFL means the OS default, i.e. the process dies at once with no KeyboardInterrupt, no finally and no with. The right value to restore is signal.default_int_handler. If the parent process started Python with SIGINT ignored, the interpreter does not install this handler and Ctrl+C does nothing at all.

Examples

import signal
signal.signal(signal.SIGINT, signal.SIG_IGN)  # временно глушим Ctrl+C
signal.signal(signal.SIGINT, signal.default_int_handler)  # а не SIG_DFL
try:
    signal.raise_signal(signal.SIGINT)
except KeyboardInterrupt:
    print('KeyboardInterrupt')  # → KeyboardInterrupt

See also

Common errors

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