KILL(2)              INTERACTIVE UNIX System              KILL(2)



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

          SYNOPSIS
               #include <signal.h>

               int kill (pid, sig)
               int pid, sig;

          DESCRIPTION
               The kill system call 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(2) 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.

               The real or effective user ID of the sending process must
               match the real or effective user ID of the receiving pro-
               cess, unless the effective user ID of the sending process is
               super-user.

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

               If pid is greater than zero, sig will be sent to the process
               whose process ID is equal to pid.  Pid may equal 1.

               If pid is 0, sig will be sent to all processes excluding
               proc0 and proc1 whose process group ID is equal to the pro-
               cess group ID of the sender.

               If pid is -1 and the effective user ID of the sender is not
               super-user, 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 -1 and the effective user ID of the sender is
               super-user, sig will be sent to all processes excluding
               proc0 and proc1.

               If pid is negative but not -1, sig will be sent to all
               processes whose process group ID is equal to the absolute
               value of pid.

               The kill system call will fail and no signal will be sent if
               one or more of the following is true:

               [EINVAL]       Sig is not a valid signal number.



          Rev. C Software Development Set                            Page 1

          KILL(2)              INTERACTIVE UNIX System              KILL(2)



               [EINVAL]       Sig is SIGKILL and pid is 1 (proc1).

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

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

          SEE ALSO
               getpid(2), setpgrp(2), signal(2), sigset(2).
               kill(1) in the INTERACTIVE UNIX System User's/System
               Administrator's Reference Manual.

          DIAGNOSTICS
               Upon successful completion, a value of 0 is returned.  Oth-
               erwise, a value of -1 is returned, and errno is set to indi-
               cate the error.




































          Rev. C Software Development Set                            Page 2