1.\" $NetBSD: daemon.3,v 1.8 1999/09/12 18:47:11 kleink 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 <stdlib.h> 46.Ft int 47.Fn daemon "int nochdir" "int noclose" 48.Sh DESCRIPTION 49.Pp 50The 51.Fn daemon 52function is for programs wishing to detach themselves from the 53controlling terminal and run in the background as system daemons. 54.Pp 55Unless the argument 56.Fa nochdir 57is non-zero, 58.Fn daemon 59changes the current working directory to the root (``/''). 60.Pp 61Unless the argument 62.Fa noclose 63is non-zero, 64.Fn daemon 65will redirect standard input, standard output and standard error 66to ``/dev/null''. 67.Pp 68.Sh RETURN VALUES 69On return 0 indicates success with -1 indicating error. 70.Sh ERRORS 71The function 72.Fn daemon 73may fail and set 74.Va errno 75for any of the errors specified for the library functions 76.Xr fork 2 77and 78.Xr setsid 2 . 79.Sh SEE ALSO 80.Xr fork 2 , 81.Xr setsid 2 82.Sh HISTORY 83The 84.Fn daemon 85function first appeared in 86.Bx 4.4 . 87.Sh BUGS 88.Fn daemon 89uses 90.Fn fork 91as part of its tty detachment mechanism. Consequently the process id changes 92when 93.Fn daemon 94is invoked. Processes employing 95.Fn daemon 96can not be reliably waited 97upon until 98.Fn daemon 99has been invoked. 100