1.\" $NetBSD: getnetent.3,v 1.13 2004/05/08 18:52:15 kleink 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.\" @(#)getnetent.3 8.1 (Berkeley) 6/4/93 31.\" 32.Dd May 8, 2004 33.Dt GETNETENT 3 34.Os 35.Sh NAME 36.Nm getnetent , 37.Nm getnetbyaddr , 38.Nm getnetbyname , 39.Nm setnetent , 40.Nm endnetent 41.Nd get network entry 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In netdb.h 46.Ft struct netent * 47.Fn getnetent 48.Ft struct netent * 49.Fn getnetbyname "const char *name" 50.Ft struct netent * 51.Fn getnetbyaddr "uint32_t net" "int type" 52.Fn setnetent "int stayopen" 53.Fn endnetent 54.Sh DESCRIPTION 55The 56.Fn getnetent , 57.Fn getnetbyname , 58and 59.Fn getnetbyaddr 60functions 61each return a pointer to an object with the 62following structure 63containing the broken-out 64fields of a line in the network data base as described in 65.Xr networks 5 . 66.Bd -literal -offset indent 67struct netent { 68 char *n_name; /* official name of net */ 69 char **n_aliases; /* alias list */ 70 int n_addrtype; /* net number type */ 71 uint32_t n_net; /* net number */ 72}; 73.Ed 74.Pp 75The members of this structure are: 76.Bl -tag -width n_addrtype 77.It Fa n_name 78The official name of the network. 79.It Fa n_aliases 80A zero terminated list of alternative names for the network. 81.It Fa n_addrtype 82The type of the network number returned; currently only AF_INET. 83.It Fa n_net 84The network number. Network numbers are returned in machine byte 85order. 86.El 87.Pp 88The 89.Fn getnetent 90function 91reads the next line of the file, opening the file if necessary. 92.Pp 93The 94.Fn setnetent 95function 96opens and rewinds the file. If the 97.Fa stayopen 98flag is non-zero, 99the net data base will not be closed after each call to 100.Fn getnetbyname 101or 102.Fn getnetbyaddr . 103.Pp 104The 105.Fn endnetent 106function 107closes the file. 108.Pp 109The 110.Fn getnetbyname 111function 112and 113.Fn getnetbyaddr 114sequentially search from the beginning 115of the file until a matching 116net name or 117net address and type is found, 118or until 119.Dv EOF 120is encountered. 121Network numbers are supplied in host order. 122.Sh FILES 123.Bl -tag -width /etc/networks -compact 124.It Pa /etc/networks 125.El 126.Sh DIAGNOSTICS 127Null pointer 128(0) returned on 129.Dv EOF 130or error. 131.Sh SEE ALSO 132.Xr networks 5 , 133.Xr nsswitch.conf 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