1.\" $NetBSD: daemon.3,v 1.11 2002/02/07 07:00:11 ross Exp $ 2.\" 3.\" Copyright (c) 1993 4.\" The Regents of the University of California. All rights reserved. 5.\" 6.\" Redistribution and use in source and binary forms, with or without 7.\" modification, are permitted provided that the following conditions 8.\" are met: 9.\" 1. Redistributions of source code must retain the above copyright 10.\" notice, this list of conditions and the following disclaimer. 11.\" 2. Redistributions in binary form must reproduce the above copyright 12.\" notice, this list of conditions and the following disclaimer in the 13.\" documentation and/or other materials provided with the distribution. 14.\" 3. All advertising materials mentioning features or use of this software 15.\" must display the following acknowledgement: 16.\" This product includes software developed by the University of 17.\" California, Berkeley and its contributors. 18.\" 4. Neither the name of the University nor the names of its contributors 19.\" may be used to endorse or promote products derived from this software 20.\" without specific prior written permission. 21.\" 22.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 23.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 24.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 25.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 26.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 27.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 28.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 29.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 30.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 31.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 32.\" SUCH DAMAGE. 33.\" 34.\" @(#)daemon.3 8.1 (Berkeley) 6/9/93 35.\" 36.Dd September 3, 1999 37.Dt DAEMON 3 38.Os 39.Sh NAME 40.Nm daemon 41.Nd run in the background 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.Fd #include \*[Lt]stdlib.h\*[Gt] 46.Ft int 47.Fn daemon "int nochdir" "int noclose" 48.Sh DESCRIPTION 49The 50.Fn daemon 51function is for programs wishing to detach themselves from the 52controlling terminal and run in the background as system daemons. 53.Pp 54Unless the argument 55.Fa nochdir 56is non-zero, 57.Fn daemon 58changes the current working directory to the root 59.Po 60.Pa / 61.Pc . 62.Pp 63Unless the argument 64.Fa noclose 65is non-zero, 66.Fn daemon 67will redirect standard input, standard output and standard error 68to 69.Pa /dev/null . 70.Sh RETURN VALUES 71On return 0 indicates success with -1 indicating error. 72.Sh ERRORS 73The function 74.Fn daemon 75may fail and set 76.Va errno 77for any of the errors specified for the library functions 78.Xr fork 2 79and 80.Xr setsid 2 . 81.Sh SEE ALSO 82.Xr fork 2 , 83.Xr setsid 2 84.Sh HISTORY 85The 86.Fn daemon 87function first appeared in 88.Bx 4.4 . 89.Sh BUGS 90.Fn daemon 91uses 92.Fn fork 93as part of its tty detachment mechanism. Consequently the process id changes 94when 95.Fn daemon 96is invoked. Processes employing 97.Fn daemon 98can not be reliably waited 99upon until 100.Fn daemon 101has been invoked. 102