Signals, job control and pipes

Sending signals

A process can send a signal to another process or group of processes using either kill(S) or sigsend(S):

kill(pid, signo);
	int pid, signo;

sigsend(idtype, id, signo);
	idtype_t idtype;
	id_t id;

Unless the process sending the signal is privileged, its real or effective user- ID must be equal to the receiving process's real or saved user-ID.

A process can send a signal to itself using the function raise as follows (see raise(S)):

raise ( int sig_val );

Signals can also be sent from a terminal device to the process group or session leader associated with the terminal (see termio(M)).