<operating system> A predefined message sent between two Unix processes or from the kernel to a process. Signals communicate the occurrence of unexpected external events such as the forced termination of a process by the user. Each signal has a unique number associated with it and each process has a signal handler set for each signal. Signals can be sent using the kill system call.
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Nearby terms: SIGLA « SIGMA « SIGNAL « signal » signalling rate » Signalling System 7 » signal-to-noise ratio