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.\" @(#)getprotoent.3 6.6 (Berkeley) 4/19/91 33.\" 34.Dd April 19, 1991 35.Dt GETPROTOENT 3 36.Os BSD 4.2 37.Sh NAME 38.Nm getprotoent , 39.Nm getprotobynumber , 40.Nm getprotobyname , 41.Nm setprotoent , 42.Nm endprotoent 43.Nd get protocol entry 44.Sh SYNOPSIS 45.Fd #include <netdb.h> 46.Ft struct protoent * 47.Fn getprotoent 48.Ft struct protoent * 49.Fn getprotobyname "char *name" 50.Ft struct protoent * 51.Fn getprotobynumber "int proto" 52.Fn setprotoent "int stayopen" 53.Fn endprotoent 54.Sh DESCRIPTION 55The 56.Fn getprotoent , 57.Fn getprotobyname , 58and 59.Fn getprotobynumber 60functions 61each return a pointer to an object with the 62following structure 63containing the broken-out 64fields of a line in the network protocol data base, 65.Pa /etc/protocols . 66.Bd -literal -offset indent 67.Pp 68struct protoent { 69 char *p_name; /* official name of protocol */ 70 char **p_aliases; /* alias list */ 71 int p_proto; /* protocol number */ 72}; 73.Ed 74.Pp 75The members of this structure are: 76.Bl -tag -width p_aliases 77.It Fa p_name 78The official name of the protocol. 79.It Fa p_aliases 80A zero terminated list of alternate names for the protocol. 81.It Fa p_proto 82The protocol number. 83.El 84.Pp 85The 86.Fn getprotoent 87function 88reads the next line of the file, opening the file if necessary. 89.Pp 90The 91.Fn setprotoent 92function 93opens and rewinds the file. If the 94.Fa stayopen 95flag is non-zero, 96the net data base will not be closed after each call to 97.Fn getprotobyname 98or 99.Fn getprotobynumber . 100.Pp 101The 102.Fn endprotoent 103function 104closes the file. 105.Pp 106The 107.Fn getprotobyname 108function 109and 110.Fn getprotobynumber 111sequentially search from the beginning 112of the file until a matching 113protocol name or 114protocol number is found, 115or until 116.Dv EOF 117is encountered. 118.Sh RETURN VALUES 119Null pointer 120(0) returned on 121.Dv EOF 122or error. 123.Sh FILES 124.Bl -tag -width /etc/protocols -compact 125.It Pa /etc/protocols 126.El 127.Sh SEE ALSO 128.Xr protocols 5 129.Sh HISTORY 130The 131.Fn getprotoent , 132.Fn getprotobynumber , 133.Fn getprotobyname , 134.Fn setprotoent , 135and 136.Fn endprotoent 137functions appeared in 138.Bx 4.2 . 139.Sh BUGS 140These functions use a static data space; 141if the data is needed for future use, it should be 142copied before any subsequent calls overwrite it. 143Only the Internet 144protocols are currently understood. 145