kill(2)                                                      kill(2)


       NAME
             kill - send a signal to a process or a group of processes

       SYNOPSIS
             #include <sys/types.h>
             #include <signal.h>
             int kill(pid_t pid, int sig);

       DESCRIPTION
             kill sends a signal to a process or a group of processes.  The
             process or group of processes to which the signal is to be
             sent is specified by pid.  The signal that is to be sent is
             specified by sig and is either one from the list given in
             signal [see signal(5)], or 0.  If sig is 0 (the null signal),
             error checking is performed but no signal is actually sent.
             This can be used to check the validity of pid.

             In order to send the signal to the target process (pid), the
             sending process must have permission to do so, subject to the
             following ownership restrictions:

                   The real or effective user ID of the sending process
                   must match the real or saved [from exec] user ID of the
                   receiving process, unless the sending process has the
                   P_OWNER privilege, or sig is SIGCONT and the sending
                   process has the same session ID as the receiving
                   process.

             The process with ID 0 and the process with ID 1 are special
             processes [see intro(2)] and will be referred to below as
             proc0 and proc1, respectively.

             If pid is greater than 0, sig will be sent to the process
             whose process ID is equal to pid, subject to the ownership
             restrictions, above.  pid may equal 1.

             If pid is negative but not (pid_t)-1, sig will be sent to all
             processes whose process group ID is equal to the absolute
             value of pid and for which the process has permission to send
             a signal.

             If pid is 0, sig will be sent to all processes excluding proc0
             and proc1 whose process group ID is equal to the process group
             ID of the sender.  Permission is needed to send a signal to
             process groups.



                           Copyright 1994 Novell, Inc.               Page 1

      kill(2)                                                      kill(2)


            If pid is (pid_t)-1 and the sending process does not have the
            P_OWNER privilege, sig will be sent to all processes excluding
            proc0 and proc1 whose real user ID is equal to the effective
            user ID of the sender.

            If pid is (pid_t)-1 and the sending process has the P_OWNER
            privilege, sig will be sent to all processes excluding proc0
            and proc1.

         Return Values
            On success, kill returns 0.  On failure, kill returns -1, sets
            errno to identify the error, and sends no signal.

         Errors
            In the following conditions, kill fails and sets errno to:

            EINVAL         sig is not a valid signal number.

            EPERM          sig is SIGKILL and pid is (pid_t)1 (i.e., pid
                           specifies proc1).

            EPERM          The sending process does not have the P_OWNER
                           privilege, the real or effective user ID of the
                           sending process does not match the real or
                           saved user ID of the receiving process, and the
                           calling process is not sending SIGCONT to a
                           process that shares the same session ID.

            ESRCH          No process or process group can be found
                           corresponding to that specified by pid.

      REFERENCES
            getpid(2), getsid(2), intro(2), kill(1), setpgrp(2),
            sigaction(2), signal(2), sigsend(2)

      NOTICES
            sigsend is a more versatile way to send signals to processes.
            The user is encouraged to use sigsend instead of kill.

         Considerations for Threads Programming
            Signals can be posted from one process to another via kill but
            not to specific threads within the receiving process.  See
            signal(5) for further details.  See thr_kill(3thread) for
            intra-process, thread-to-thread signaling.




                          Copyright 1994 Novell, Inc.               Page 2

       kill(2)                                                      kill(2)


          Considerations for Lightweight Processes
             Additionally, signals from one process cannot be addressed to
             specific LWPs in the receiving process.













































                           Copyright 1994 Novell, Inc.               Page 3