KILL(3B)							      KILL(3B)

NAME    [Toc]    [Back]

     kill - send signal	to a process (4.3BSD)

SYNOPSIS    [Toc]    [Back]

     #include <signal.h>

     int kill(pid_t pid, int sig);

     To	use any	of the BSD signal routines (kill(3B), killpg(3B),
     sigblock(3B), signal(3B), sigpause(3B), sigsetmask(3B), sigstack(2B),
     sigvec(3B)) you must either

     1)	#define	_BSD_SIGNALS or	_BSD_COMPAT before including <signal.h>, or

     2)	specify	one of them in the compile command or makefile:

	  cc -D_BSD_SIGNALS -o prog prog.c

DESCRIPTION    [Toc]    [Back]

     kill sends	the signal sig to a process, specified by the process number
     pid.  Sig may be one of the signals specified in sigvec(3B), or it	may be
     0,	in which case error checking is	performed but no signal	is actually
     sent. This	can be used to check the validity of pid.

     The sending and receiving processes must have the same effective user ID,
     otherwise this call is restricted to the super-user.  A single exception
     is	the signal SIGCONT, which may always be	sent to	any descendant of the
     current process.

     If	the process number is 0, the signal is sent to all processes in	the
     sender's process group; this is a variant of killpg(3B).

     If	the process number is -1 and the user is the super-user, the signal is
     broadcast universally except to system processes.	If the process number
     is	-1 and the user	is not the super-user, the signal is broadcast
     universally to all	processes with the same	uid as the user.  No error is
     returned if any process could be signaled.

     For compatibility with System V, if the process number is negative	but
     not -1, the signal	is sent	to all processes whose process group ID	is
     equal to the absolute value of the	process	number.	 This is a variant of
     killpg(3B).

     Processes may send	signals	to themselves.

RETURN VALUE    [Toc]    [Back]

     Upon successful completion, a value of 0 is returned.  Otherwise, a value
     of	-1 is returned and errno is set	to indicate the	error.






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KILL(3B)							      KILL(3B)

ERRORS    [Toc]    [Back]

     kill will fail and	no signal will be sent if any of the following occur:

     [EINVAL]	    Sig	is not a valid signal number.

     [ESRCH]	    No process can be found corresponding to that specified by
		    pid.

     [ESRCH]	    The	process	id was given as	0 but the sending process does
		    not	have a process group.

     [EPERM]	    The	sending	process	is not the super-user and its
		    effective user ID does not match the effective user	ID of
		    the	receiving process.

SEE ALSO    [Toc]    [Back]

     getpid(2),	getpgrp(2), killpg(3B),	sigvec(3B)

CAVEATS	(IRIX)
     When the process number is	-1, the	process	sending	the signal is NOT
     included in the delivery group.  In the IRIX implementation, the sending
     process receives the signal, too.

     4.3BSD's implementation of	kill returns EPERM if any members of a process
     group can not be signaled (when kill is invoked with a pid	of 0).	The
     IRIX implementation does not.

WARNING	(IRIX)
     The 4.3BSD	and System V signal facilities have different semantics.
     Using both	facilities in the same program is strongly discouraged and
     will result in unpredictable behavior.


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