1.\" $NetBSD: getnetent.3,v 1.10 2002/02/07 07:00:20 ross Exp $ 2.\" 3.\" Copyright (c) 1983, 1991, 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.\" @(#)getnetent.3 8.1 (Berkeley) 6/4/93 35.\" 36.Dd January 16, 1999 37.Dt GETNETENT 3 38.Os 39.Sh NAME 40.Nm getnetent , 41.Nm getnetbyaddr , 42.Nm getnetbyname , 43.Nm setnetent , 44.Nm endnetent 45.Nd get network entry 46.Sh LIBRARY 47.Lb libc 48.Sh SYNOPSIS 49.Fd #include \*[Lt]netdb.h\*[Gt] 50.Ft struct netent * 51.Fn getnetent 52.Ft struct netent * 53.Fn getnetbyname "const char *name" 54.Ft struct netent * 55.Fn getnetbyaddr "long net" "int type" 56.Fn setnetent "int stayopen" 57.Fn endnetent 58.Sh DESCRIPTION 59The 60.Fn getnetent , 61.Fn getnetbyname , 62and 63.Fn getnetbyaddr 64functions 65each return a pointer to an object with the 66following structure 67containing the broken-out 68fields of a line in the network data base as described in 69.Xr networks 5 . 70.Bd -literal -offset indent 71struct netent { 72 char *n_name; /* official name of net */ 73 char **n_aliases; /* alias list */ 74 int n_addrtype; /* net number type */ 75 unsigned long n_net; /* net number */ 76}; 77.Ed 78.Pp 79The members of this structure are: 80.Bl -tag -width n_addrtype 81.It Fa n_name 82The official name of the network. 83.It Fa n_aliases 84A zero terminated list of alternative names for the network. 85.It Fa n_addrtype 86The type of the network number returned; currently only AF_INET. 87.It Fa n_net 88The network number. Network numbers are returned in machine byte 89order. 90.El 91.Pp 92The 93.Fn getnetent 94function 95reads the next line of the file, opening the file if necessary. 96.Pp 97The 98.Fn setnetent 99function 100opens and rewinds the file. If the 101.Fa stayopen 102flag is non-zero, 103the net data base will not be closed after each call to 104.Fn getnetbyname 105or 106.Fn getnetbyaddr . 107.Pp 108The 109.Fn endnetent 110function 111closes the file. 112.Pp 113The 114.Fn getnetbyname 115function 116and 117.Fn getnetbyaddr 118sequentially search from the beginning 119of the file until a matching 120net name or 121net address and type is found, 122or until 123.Dv EOF 124is encountered. 125Network numbers are supplied in host order. 126.Sh FILES 127.Bl -tag -width /etc/networks -compact 128.It Pa /etc/networks 129.El 130.Sh DIAGNOSTICS 131Null pointer 132(0) returned on 133.Dv EOF 134or error. 135.Sh SEE ALSO 136.Xr networks 5 , 137.Xr nsswitch.conf 5 138.Sh HISTORY 139The 140.Fn getnetent , 141.Fn getnetbyaddr , 142.Fn getnetbyname , 143.Fn setnetent , 144and 145.Fn endnetent 146functions appeared in 147.Bx 4.2 . 148.Sh BUGS 149The data space used by 150these functions is static; if future use requires the data, it should be 151copied before any subsequent calls to these functions overwrite it. 152Only Internet network 153numbers are currently understood. 154Expecting network numbers to fit 155in no more than 32 bits is probably 156naive. 157