1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. 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. Neither the name of the University nor the names of its contributors 13.\" may be used to endorse or promote products derived from this software 14.\" without specific prior written permission. 15.\" 16.\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND 17.\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE 18.\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE 19.\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE 20.\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL 21.\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS 22.\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) 23.\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT 24.\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY 25.\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF 26.\" SUCH DAMAGE. 27.\" 28.\" @(#)getprotoent.3 8.1 (Berkeley) 6/4/93 29.\" $FreeBSD: src/lib/libc/net/getprotoent.3,v 1.12 2007/01/09 00:28:02 imp Exp $ 30.\" $DragonFly: src/lib/libc/net/getprotoent.3,v 1.3 2008/05/01 21:51:43 swildner Exp $ 31.\" 32.Dd June 4, 1993 33.Dt GETPROTOENT 3 34.Os 35.Sh NAME 36.Nm getprotoent , 37.Nm getprotobynumber , 38.Nm getprotobyname , 39.Nm setprotoent , 40.Nm endprotoent 41.Nd get protocol entry 42.Sh LIBRARY 43.Lb libc 44.Sh SYNOPSIS 45.In netdb.h 46.Ft struct protoent * 47.Fn getprotoent void 48.Ft struct protoent * 49.Fn getprotobyname "const char *name" 50.Ft struct protoent * 51.Fn getprotobynumber "int proto" 52.Ft void 53.Fn setprotoent "int stayopen" 54.Ft void 55.Fn endprotoent void 56.Sh DESCRIPTION 57The 58.Fn getprotoent , 59.Fn getprotobyname , 60and 61.Fn getprotobynumber 62functions 63each return a pointer to an object with the 64following structure 65containing the broken-out 66fields of a line in the network protocol data base, 67.Pa /etc/protocols . 68.Bd -literal -offset indent 69struct protoent { 70 char *p_name; /* official name of protocol */ 71 char **p_aliases; /* alias list */ 72 int p_proto; /* protocol number */ 73}; 74.Ed 75.Pp 76The members of this structure are: 77.Bl -tag -width p_aliases 78.It Fa p_name 79The official name of the protocol. 80.It Fa p_aliases 81A zero terminated list of alternate names for the protocol. 82.It Fa p_proto 83The protocol number. 84.El 85.Pp 86The 87.Fn getprotoent 88function 89reads the next line of the file, opening the file if necessary. 90.Pp 91The 92.Fn setprotoent 93function 94opens and rewinds the file. 95If the 96.Fa stayopen 97flag is non-zero, 98the net data base will not be closed after each call to 99.Fn getprotobyname 100or 101.Fn getprotobynumber . 102.Pp 103The 104.Fn endprotoent 105function 106closes the file. 107.Pp 108The 109.Fn getprotobyname 110function 111and 112.Fn getprotobynumber 113sequentially search from the beginning 114of the file until a matching 115protocol name or 116protocol number is found, 117or until 118.Dv EOF 119is encountered. 120.Sh RETURN VALUES 121Null pointer 122(0) returned on 123.Dv EOF 124or error. 125.Sh FILES 126.Bl -tag -width /etc/protocols -compact 127.It Pa /etc/protocols 128.El 129.Sh SEE ALSO 130.Xr protocols 5 131.Sh HISTORY 132The 133.Fn getprotoent , 134.Fn getprotobynumber , 135.Fn getprotobyname , 136.Fn setprotoent , 137and 138.Fn endprotoent 139functions appeared in 140.Bx 4.2 . 141.Sh BUGS 142These functions use a thread-specific data space; 143if the data is needed for future use, it should be 144copied before any subsequent calls overwrite it. 145Only the Internet 146protocols are currently understood. 147