kill(2) — CLIX 3.1r7.6.22



  kill(2)                             CLIX                             kill(2)



  NAME

    kill - Sends a signal to a process or to a group of processes

  LIBRARY

    Standard I/O Library (libc.a)

  SYNOPSIS

    int kill(
      pid_t process ,
      int signal );

  PARAMETERS

    process   Specifies the process or group of processes.  The processes that
              have the process IDs 0 and 1 are special processes and are
              sometimes referred to here as proc0 and proc1, respectively.

              If the process parameter has a value greater than 0, the signal
              specified by the signal parameter is sent to the process that
              has a process ID equal to the value of the process parameter.
              The process parameter may equal 1.

              If the process parameter is equal to 0, the signal specified by
              the signal parameter is sent to all of the processes, excluding
              proc0 and proc1, for which the process group ID is equal to the
              process group ID of the sender.

              If the process parameter is equal to -1 and the effective user
              ID of the sender is not superuser, the signal specified by the
              signal parameter is sent to all processes for which the real
              user ID is equal to the effective user ID of the sender,
              excluding proc0 and proc1.

              If the process parameter is equal to -1 and the effective user
              ID of the sender is superuser, the signal specified by the
              signal parameter is sent to all of the processes, excluding
              proc0 and proc1.

              If the process parameter is negative but not -1, the signal
              specified by the signal parameter is sent to all processes that
              have a process group ID equal to the absolute value of the
              process parameter.

    signal    Specifies the signal and is either a value from the list given
              in the signal() function, or 0.  If the signal parameter is 0
              (the null signal), error checking is performed but no signal is
              sent.  This can be used to check the validity of the process
              parameter.



  2/94 - Intergraph Corporation                                              1



  kill(2)                             CLIX                             kill(2)



  DESCRIPTION

    The kill() function sends the signal specified by the signal parameter to
    the process or group of processes specified by the process parameter.

    To send a signal to another process, either the real or the effective user
    ID of the sending process must match the real or effective user ID of the
    receiving process, unless the effective user ID of the sending process is
    superuser.

  EXAMPLES

    1.  To send a SIGUSR1 to a given process:

        if (kill(pid, SIGUSR1) == -1)
                perror("Could not kill process");


    2.  To send a SIGKILL to all processes in a given process group:

        if (kill(-pgrp, SIGKILL) == -1)
                perror("Could not kill process group");


  RETURN VALUES

    Upon successful completion, kill() returns a value of 0.  Otherwise, a
    value of -1 is returned and the global variable errno is set to indicate
    the error.

  ERRORS

    The kill() function fails and no signal is sent if one or more of the
    following are true:

    [EINVAL]   The signal parameter is not a valid signal number.

    [EINVAL]   The signal parameter is SIGKILL and the process parameter is 1
               (proc1).

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

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

  RELATED INFORMATION

    Commands: kill(1)




  2                                              Intergraph Corporation - 2/94



  kill(2)                             CLIX                             kill(2)



    Functions: getpid(2), killpg(2), raise(2), setpgrp(2), sigaction(2),
    signal(2), sigset(2)




















































  2/94 - Intergraph Corporation                                              3

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