signal — OS Signal Handling¶

Register handlers for Unix signals like SIGINT, SIGTERM, and more.

Platform support

The signal module currently requires macOS or Linux. Windows support (via SetConsoleCtrlHandler for Ctrl+C/close events) is planned.

Import¶

import signal

Signal Constants¶

Constant	Value	Description
`signal.SIGINT`	2	Interrupt (Ctrl+C)
`signal.SIGTERM`	15	Termination
`signal.SIGHUP`	1	Hangup
`signal.SIGQUIT`	3	Quit
`signal.SIGUSR1`	10	User-defined 1
`signal.SIGUSR2`	12	User-defined 2
`signal.SIGALRM`	14	Alarm
`signal.SIGPIPE`	13	Broken pipe

API Reference¶

Function	Description
`signal.on(signum, handler)`	Register a handler for a signal
`signal.on_interrupt(handler)`	Shortcut: register SIGINT handler
`signal.on_terminate(handler)`	Shortcut: register SIGTERM handler
`signal.reset(signum)`	Reset signal to default behavior
`signal.ignore(signum)`	Ignore a signal
`signal.send(signum)`	Send a signal to the current process
`signal.name(signum) -> str`	Get human-readable name for a signal

Examples¶

Catch Ctrl+C¶

import signal

def main() -> int:
    signal.on_interrupt(lambda:
        print("Caught Ctrl+C! Shutting down...")
        0
    )

    # Your long-running program here
    print("Press Ctrl+C to stop")
    while true:
        pass
    0

Graceful Shutdown¶

import signal

let running = true

def main() -> int:
    signal.on_terminate(lambda:
        print("SIGTERM received, cleaning up...")
        running = false
        0
    )

    while running:
        # Do work
        pass

    print("Shutdown complete")
    0

Signal Names¶

import signal

def main() -> int:
    print(signal.name(signal.SIGINT))   # SIGINT
    print(signal.name(signal.SIGTERM))  # SIGTERM
    print(signal.name(signal.SIGHUP))   # SIGHUP
    0

Ignore SIGPIPE¶

import signal

def main() -> int:
    signal.ignore(signal.SIGPIPE)
    # Write to closed pipes won't crash the program
    0

Comparison¶

Desi	Python	Go	Rust
`signal.on(sig, fn)`	`signal.signal(sig, fn)`	`signal.Notify(ch, sig)`	`ctrlc::set_handler(fn)`
`signal.on_interrupt(fn)`	`signal.signal(SIGINT, fn)`	Manual	`ctrlc::set_handler(fn)`
`signal.ignore(sig)`	`signal.signal(sig, SIG_IGN)`	`signal.Ignore(sig)`	Manual
`signal.name(sig)`	`signal.Signals(sig).name`	N/A	N/A