1.\" Copyright (c) 1983, 1991 The Regents of the University of California. 2.\" All rights reserved. 3.\" 4.\" Redistribution and use in source and binary forms, with or without 5.\" modification, are permitted provided that the following conditions 6.\" are met: 7.\" 1. Redistributions of source code must retain the above copyright 8.\" notice, this list of conditions and the following disclaimer. 9.\" 2. Redistributions in binary form must reproduce the above copyright 10.\" notice, this list of conditions and the following disclaimer in the 11.\" documentation and/or other materials provided with the distribution. 12.\" 3. All advertising materials mentioning features or use of this software 13.\" must display the following acknowledgement: 14.\" This product includes software developed by the University of 15.\" California, Berkeley and its contributors. 16.\" 4. Neither the name of the University nor the names of its contributors 17.\" may be used to endorse or promote products derived from this software 18.\" without specific prior written permission. 19.\" 20.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 21.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 22.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 23.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 24.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 25.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 26.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 27.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 28.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 29.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 30.\" SUCH DAMAGE. 31.\" 32.\" from: @(#)getnetent.3 6.6 (Berkeley) 4/19/91 33.\" $Id: getnetent.3,v 1.2 1993/08/01 07:45:21 mycroft Exp $ 34.\" 35.Dd April 19, 1991 36.Dt GETNETENT 3 37.Os BSD 4.2 38.Sh NAME 39.Nm getnetent , 40.Nm getnetbyaddr , 41.Nm getnetbyname , 42.Nm setnetent , 43.Nm endnetent 44.Nd get network entry 45.Sh SYNOPSIS 46.Fd #include <netdb.h> 47.Ft struct netent * 48.Fn getnetent 49.Ft struct netent * 50.Fn getnetbyname "char *name" 51.Ft struct netent * 52.Fn getnetbyaddr "long net" "int type" 53.Fn setnetent "int stayopen" 54.Fn endnetent 55.Sh DESCRIPTION 56The 57.Fn getnetent , 58.Fn getnetbyname , 59and 60.Fn getnetbyaddr 61functions 62each return a pointer to an object with the 63following structure 64containing the broken-out 65fields of a line in the network data base, 66.Pa /etc/networks . 67.Bd -literal -offset indent 68struct netent { 69 char *n_name; /* official name of net */ 70 char **n_aliases; /* alias list */ 71 int n_addrtype; /* net number type */ 72 unsigned long n_net; /* net number */ 73}; 74.Ed 75.Pp 76The members of this structure are: 77.Bl -tag -width n_addrtype 78.It Fa n_name 79The official name of the network. 80.It Fa n_aliases 81A zero terminated list of alternate names for the network. 82.It Fa n_addrtype 83The type of the network number returned; currently only AF_INET. 84.It Fa n_net 85The network number. Network numbers are returned in machine byte 86order. 87.El 88.Pp 89The 90.Fn getnetent 91function 92reads the next line of the file, opening the file if necessary. 93.Pp 94The 95.Fn setnetent 96function 97opens and rewinds the file. If the 98.Fa stayopen 99flag is non-zero, 100the net data base will not be closed after each call to 101.Fn getnetbyname 102or 103.Fn getnetbyaddr . 104.Pp 105The 106.Fn endnetent 107function 108closes the file. 109.Pp 110The 111.Fn getnetbyname 112function 113and 114.Fn getnetbyaddr 115sequentially search from the beginning 116of the file until a matching 117net name or 118net address and type is found, 119or until 120.Dv EOF 121is encountered. 122Network numbers are supplied in host order. 123.Sh FILES 124.Bl -tag -width /etc/networks -compact 125.It Pa /etc/networks 126.El 127.Sh DIAGNOSTICS 128Null pointer 129(0) returned on 130.Dv EOF 131or error. 132.Sh SEE ALSO 133.Xr networks 5 134.Sh HISTORY 135The 136.Fn getnetent , 137.Fn getnetbyaddr , 138.Fn getnetbyname , 139.Fn setnetent , 140and 141.Fn endnetent 142functions appeared in 143.Bx 4.2 . 144.Sh BUGS 145The data space used by 146these functions is static; if future use requires the data, it should be 147copied before any subsequent calls to these functions overwrite it. 148Only Internet network 149numbers are currently understood. 150Expecting network numbers to fit 151in no more than 32 bits is probably 152naive. 153