1.\" $OpenBSD: getnetent.3,v 1.19 2019/08/30 20:20:51 jmc 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. Neither the name of the University nor the names of its contributors 15.\" may be used to endorse or promote products derived from this software 16.\" without specific prior written permission. 17.\" 18.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 19.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 20.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 21.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 22.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 23.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 24.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 25.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 26.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 27.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 28.\" SUCH DAMAGE. 29.\" 30.Dd $Mdocdate: August 30 2019 $ 31.Dt GETNETENT 3 32.Os 33.Sh NAME 34.Nm getnetent , 35.Nm getnetbyaddr , 36.Nm getnetbyname , 37.Nm setnetent , 38.Nm endnetent 39.Nd get network entry 40.Sh SYNOPSIS 41.In netdb.h 42.Ft struct netent * 43.Fn getnetent "void" 44.Ft struct netent * 45.Fn getnetbyname "const char *name" 46.Ft struct netent * 47.Fn getnetbyaddr "in_addr_t net" "int type" 48.Ft void 49.Fn setnetent "int stayopen" 50.Ft void 51.Fn endnetent "void" 52.Sh DESCRIPTION 53The 54.Fn getnetbyname 55and 56.Fn getnetbyaddr 57functions return a pointer to an object with the following structure: 58.Bd -literal -offset indent 59struct netent { 60 char *n_name; /* official name of net */ 61 char **n_aliases; /* alias list */ 62 int n_addrtype; /* net number type */ 63 in_addr_t n_net; /* net number */ 64}; 65.Ed 66.Pp 67The members of this structure are: 68.Bl -tag -width n_addrtype 69.It Fa n_name 70The official name of the network. 71.It Fa n_aliases 72A null-terminated list of alternate names for the network. 73.It Fa n_addrtype 74The type of the network number returned; it is always 75.Dv AF_INET . 76.It Fa n_net 77The network number. 78Network numbers are returned in machine byte order. 79.El 80.Pp 81On 82.Ox , 83these legacy functions perform a lookup in a similar fashion as 84.Xr gethostbyname 3 85and 86.Xr gethostbyaddr 3 , 87respectively. 88On other systems, they may use a separate network database file, 89.Pa /etc/networks . 90.Pp 91In contrast to 92.Xr gethostbyaddr 3 , 93the 94.Fa net 95argument is expected in machine byte order. 96.Pp 97The 98.Fn setnetent , 99.Fn getnetent , 100and 101.Fn endnetent 102functions are deprecated and no longer have any effect. 103They could be used in the past to iterate over entries in the former file 104.Pa /etc/networks . 105.Sh RETURN VALUES 106The 107.Fn getnetbyaddr 108and 109.Fn getnetbyname 110functions return 111.Dv NULL 112if the requested entry is not found. 113.Pp 114The 115.Fn getnetent 116function always returns 117.Dv NULL . 118.Sh FILES 119.Bl -tag -width /etc/hosts -compact 120.It Pa /etc/hosts 121The local host and network name database. 122.El 123.Sh SEE ALSO 124.Xr getaddrinfo 3 , 125.Xr gethostbyname 3 , 126.Xr getnameinfo 3 , 127.Xr res_init 3 , 128.Xr hosts 5 129.Sh STANDARDS 130These functions conform to 131.St -p1003.1-2008 . 132.Sh HISTORY 133The 134.Fn getnetent , 135.Fn getnetbyaddr , 136.Fn getnetbyname , 137.Fn setnetent , 138and 139.Fn endnetent 140functions appeared in 141.Bx 4.2 . 142.Sh BUGS 143The data space used by these functions is static; if future use 144requires the data, it should be copied before any subsequent calls 145to these functions overwrite it. 146Only Internet network numbers are currently understood. 147Expecting network numbers to fit in no more than 32 bits is naive. 148