SIGNAL
A synchronous language by Le Guernic et al of INRIA.
["SIGNAL - A Data Flow-Oriented Language for Signal Processing," P. le Guernic, IEEE Trans Acoustics Speech & Signal Proc, ASSP-34(2):362-1986-04-374].
signal
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.