94 lines
2.5 KiB
Groff
94 lines
2.5 KiB
Groff
.\" Copyright (c) 1980 Regents of the University of California.
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.\" All rights reserved. The Berkeley software License Agreement
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.\" specifies the terms and conditions for redistribution.
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.\"
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.\" @(#)kill.2 6.5 (Berkeley) 5/14/86
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.\"
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.TH KILL 2 "May 14, 1986"
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.UC 4
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.SH NAME
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kill \- send signal to a process
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.SH SYNOPSIS
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.nf
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.ft B
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#include <sys/types.h>
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#include <signal.h>
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int kill(pid_t \fIpid\fP, int \fIsig\fP)
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.ft R
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.fi
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.SH DESCRIPTION
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.B Kill
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sends the signal \fIsig\fP
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to a process, specified by the process number
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.IR pid .
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.I Sig
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may be one of the signals specified in
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.BR sigaction (2),
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or it may be 0, in which case
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error checking is performed but no
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signal is actually sent.
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This can be used to check the validity of
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.IR pid .
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.PP
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The sending and receiving processes must
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have the same effective user ID, otherwise
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this call is restricted to the super-user.
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.ig
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A single exception is the signal SIGCONT, which may always be sent
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to any descendant of the current process.
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..
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.PP
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If the process number is 0,
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the signal is sent to all processes in the
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sender's process group.
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.PP
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If the process number is \-1
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and the user is the super-user,
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the signal is broadcast universally
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except to
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.B init
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and the process sending the signal.
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If the process number is \-1
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and the user is not the super-user,
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the signal is broadcast universally to
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all processes with the same uid as the user
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except the process sending the signal.
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No error is returned if any process could be signaled.
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.PP
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If the process number is negative but not \-1,
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the signal is sent to all processes whose process group ID
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is equal to the absolute value of the process number.
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.PP
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Processes may send signals to themselves.
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.SH "RETURN VALUE
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Upon successful completion, a value of 0 is returned.
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Otherwise, a value of \-1 is returned and
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.B errno
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is set to indicate the error.
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.SH "ERRORS
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.B Kill
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will fail and no signal will be sent if any of the following
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occur:
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.TP 15
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[EINVAL]
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\fISig\fP is not a valid signal number.
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.TP 15
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[ESRCH]
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No process can be found corresponding to that specified by \fIpid\fP.
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.TP 15
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[ESRCH]
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The process id was given as 0
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but the sending process does not have a process group.
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.TP 15
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[EPERM]
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The sending process is not the super-user and its effective
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user id does not match the effective user-id of the receiving process.
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When signaling a process group, this error was returned if any members
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of the group could not be signaled.
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.SH "SEE ALSO"
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.BR getpid (2),
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.BR getpgrp (2),
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.BR sigaction (2),
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.BR raise (3).
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