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kill(2)
NAME
  kill - Sends 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 X/Open standards, but may be required on
  other vendors' systems that conform to these standards.

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

  kill():  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 calling 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 which have a process
  group ID equal to the absolute value of the process parameter.

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.

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.

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
	    privilege.

RELATED INFORMATION
  Functions: getpid(2), killpg(2), raise(3), setpgid(2), sigaction(2),
  sigvec(2)


  Standards: standards(5)

Index for Section 2

Alphabetical listing for K

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