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kill(2)
NAME
  kill - Send a signal to a process or to a group of processes

SYNOPSIS
  #include <signal.h>

  int kill(
	  pid_t process,
	  int signal );

  Application developers may want to specify an #include statement for
  <sys/types.h> before the one for <signal.h> if programs are being developed
  for multiple platforms. The additional #include statement is not required
  on Tru64 UNIX systems or by ISO or XSH specifications, but may be on other
  vendors' systems that conform to these standards.

STANDARDS
  Interfaces documented on this reference page conform to industry standards
  as follows:

  kill():  XSH4.0, XSH4.2, XSH5.0

  Refer to the standards(5) reference page for more information about
  industry standards and associated tags.

PARAMETERS
  process
      Specifies the process or group of processes.

  signal
      Specifies the signal.  If the signal parameter is a value of 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.

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, at least one of the following must be
  true:

    ·  The real or the saved set-user-ID of the sending process matches the
       real or effective user ID of the receiving process.

    ·  The process is trying to send the SIGCONT signal to one of its
       session's processes.

    ·  The process has root privileges.

  Processes can send signals to themselves.

  Sending a signal does not imply that the operation is successful. All
  signal operations must pass the access checks prescribed by each enforced
  access control policy on the system.

  If the process parameter is greater than 0 (zero), 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.

  If the process parameter is equal to 0 (zero), the signal specified by the
  signal parameter is sent to all of the processes (other than system
  processes) whose process group ID is equal to the process group ID of the
  sender.

  If the process parameter is equal to -1, the signal specified by the signal
  parameter is sent to all of the processes other than system processes for
  which the process has permission to send that signal. For example, if the
  effective user ID of the sender has root privileges, the signal specified
  by the signal parameter is sent to all of the processes other than system
  processes.

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

  [Tru64 UNIX]	In a TruCluster Server cluster, if the process parameter is
  greater than 0 (zero), 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, even if that process is on another cluster member. The process
  ID is guaranteed to be unique across the cluster.

  [Tru64 UNIX]	In a TruCluster Server cluster, if the process parameter is
  equal to -1, the signal specified by the signal parameter is sent to all
  non-system processes (on the current cluster member) for which the process
  has permission to send that signal.

  [Tru64 UNIX]	In a TruCluster Server cluster, if the process parameter is
  negative but not -1, the signal specified by the signal parameter is sent
  to all of the processes that have a process group ID equal to the absolute
  value of the process parameter, even if those processes are on another
  cluster member.

NOTES
  Some applications and scripts depend on the process ID of the init program
  being 1 (one): do not depend on it. Instead, use standard methods, such as
  the ps and grep commands, to obtain all process IDs.

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

ERRORS
  The kill() function sets errno to the specified values for the following
  conditions:

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

      [Tru64 UNIX]  The signal parameter is SIGKILL, SIGSTOP, SIGTSTP or
      SIGCONT and the process parameter is the process ID of the init
      program.

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

  [EPERM]
      The real or saved user ID does not match the real or effective user ID
      of the receiving process, the calling process does not have appropriate
      privilege, and the process is not sending a SIGCONT signal to one of
      its session's processes.

  [EACCES]
      [Tru64 UNIX]  The calling process does not have appropriate privileges.

SEE ALSO
  Functions: getpid(2), killpg(2), setpgid(2), sigaction(2), sigvec(2),
  raise(3)

  Standards: standards(5)

Index for Section 2

Alphabetical listing for K

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