killpg

Purpose

     Sends a signal to a process group.

Library

     Berkeley Library (libbsd.a)

Syntax

     int killpg (pgrp, sig)
     int pgrp, sig;

Description

     The killpg  subroutine sends the signal  specified by the
     sig parameter to the process group in the pgrp parameter.

     If the sending process does not have an effective user ID
     of superuser,  the sending process and  the process group
     members must have the same user ID or the call fails.

     The    killpg    subroutine     is    implemented    with
     kill(-(pgrp), sig);, so  it cannot be used  to signal all
     descendants of the init process.   For example, a call to
     killpg similar to the following:

       killpg(1, SIGXXX)

     does, however, result in all processes in process group 1
     except init receiving the signal.

Return Value

     When the call succeeds, a value of 0 is returned.  If the
     killpg subroutine  fails, a value  of -1 is  returned and
     errno is set to indicate the error.

Diagnostics

     The killpg subroutine fails and  no signal is sent if one
     or more of the following is true:

     EINVAL     The sig parameter is not a valid signal.

     ESRCH      No process exists in  the process group speci-
                fied by pgrp.

     ESRCH      The  pgrp  parameter  is 0,  but  the  sending
                process does not have a process group.

     EPERM      The sending process does not have an effective
                user ID  of superuser,  and the sender  and at
                least one target process have different effec-
                tive user IDs.

Related Information

     In this  book:  "getpid,  getpgrp, getppid,"  "kill," and
     "sigvec."