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kill(2) [bsd man page]

KILL(2) 							System Calls Manual							   KILL(2)

NAME
kill - send signal to a process SYNOPSIS
kill(pid, sig) int pid, sig; DESCRIPTION
Kill sends the signal sig to a process, specified by the process number pid. Sig may be one of the signals specified in sigvec(2), or it may be 0, in which case error checking is performed but no signal is actually sent. This can be used to check the validity of pid. The sending and receiving processes must have the same effective user ID, otherwise this call is restricted to the super-user. A single exception is the signal SIGCONT, which may always be sent to any descendant of the current process. If the process number is 0, the signal is sent to all processes in the sender's process group; this is a variant of killpg(2). If the process number is -1 and the user is the super-user, the signal is broadcast universally except to system processes and the process sending the signal. If the process number is -1 and the user is not the super-user, the signal is broadcast universally to all processes with the same uid as the user except the process sending the signal. No error is returned if any process could be signaled. For compatibility with System V, if the process number is negative but not -1, the signal is sent to all processes whose process group ID is equal to the absolute value of the process number. This is a variant of killpg(2). Processes may send signals to themselves. RETURN VALUE
Upon successful completion, a value of 0 is returned. Otherwise, a value of -1 is returned and errno is set to indicate the error. ERRORS
Kill will fail and no signal will be sent if any of the following occur: [EINVAL] Sig is not a valid signal number. [ESRCH] No process can be found corresponding to that specified by pid. [ESRCH] The process id was given as 0 but the sending process does not have a process group. [EPERM] The sending process is not the super-user and its effective user id does not match the effective user-id of the receiving process. When signaling a process group, this error was returned if any members of the group could not be signaled. SEE ALSO
getpid(2), getpgrp(2), killpg(2), sigvec(2) 4th Berkeley Distribution May 14, 1986 KILL(2)

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kill(2) 							System Calls Manual							   kill(2)

Name
       kill - send signal to a process

Syntax
       #include <sys/types.h>
       #include <signal.h>

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

Description
       The  system  call sends the signal sig to a process specified by the process number pid.  The sig can be a signal specified in a call or it
       can be 0.  If the sig is 0, error checking is performed, but a signal is not sent.  This call can be used to check the validity of pid.

       The sending and receiving processes must have the same effective user ID, otherwise this call is  restricted  to  the  superuser  with  the
       exception of the signal SIGCONT.  The signal SIGCONT can always be sent to a child or grandchild of the current process.

       If the process number is 0, the signal is sent to all other processes in the sender's process group.

       If  the process number is negative but not -1, the signal is sent to all processes whose process-group-id is equal to the absolute value of
       the process number.

       The above two options are variants of

       If the process number is -1, and the user is the superuser, the signal is broadcast for all processes except to system  processes  and  the
       process sending the signal.

       Processes may send signals to themselves.

Environment
       System Five
       POSIX

       When  your  program  is	compiled in the System V or POSIX environment, a signal is sent if either the real or effective uid of the sending
       process matches the real or saved-set-uid (as described in ) of the receiving process. In addition, any process can use a pid  of  -1,  and
       the signal is sent to all processes subject to these permission checks.

       In POSIX mode, the pid argument is of type pid_t.

Return Values
       Upon successful completion, a value of 0 is returned.  Otherwise, a value of -1 is returned, and is set to indicate the error.

Diagnostics
       The system call fails under the following conditions:

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

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

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

See Also
       execve(2), getpgrp(2), getpid(2), killpg(2), sigvec(2), pause(3)

																	   kill(2)

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