.\" Copyright (c) 1983, 1991, 1993 .\" The Regents of the University of California. All rights reserved. .\" .\" Redistribution and use in source and binary forms, with or without .\" modification, are permitted provided that the following conditions .\" are met: .\" 1. Redistributions of source code must retain the above copyright .\" notice, this list of conditions and the following disclaimer. .\" 2. Redistributions in binary form must reproduce the above copyright .\" notice, this list of conditions and the following disclaimer in the .\" documentation and/or other materials provided with the distribution. .\" 3. All advertising materials mentioning features or use of this software .\" must display the following acknowledgement: .\" This product includes software developed by the University of .\" California, Berkeley and its contributors. .\" 4. Neither the name of the University nor the names of its contributors .\" may be used to endorse or promote products derived from this software .\" without specific prior written permission. .\" .\" THIS SOFTWARE IS PROVIDED BY THE REGENTS AND CONTRIBUTORS ``AS IS'' AND .\" ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE .\" IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE .\" ARE DISCLAIMED. IN NO EVENT SHALL THE REGENTS OR CONTRIBUTORS BE LIABLE .\" FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL .\" DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS .\" OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) .\" HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT .\" LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY .\" OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF .\" SUCH DAMAGE. .\" .\" @(#)getprotoent.3 8.1 (Berkeley) 6/4/93 .\" $FreeBSD: src/lib/libc/net/getprotoent.3,v 1.4.2.3 2001/08/17 15:42:38 ru Exp $ .\" .Dd June 4, 1993 .Dt GETPROTOENT 3 .Os .Sh NAME .Nm endprotoent , .Nm getprotobyname , .Nm getprotobynumber , .Nm getprotoent , .Nm setprotoent .Nd get protocol entry .Sh LIBRARY .Lb libc .Sh SYNOPSIS .Fd #include .Ft void .Fo endprotoent .Fa void .Fc .Ft struct protoent * .Fo getprotobyname .Fa "const char *name" .Fc .Ft struct protoent * .Fo getprotobynumber .Fa "int proto" .Fc .Ft struct protoent * .Fo getprotoent .Fa void .Fc .Ft void .Fo setprotoent .Fa "int stayopen" .Fc .Sh DESCRIPTION The .Fn getprotoent , .Fn getprotobyname , and .Fn getprotobynumber functions each return a pointer to an object with the following structure containing the broken-out fields of a line in the network protocol data base, .Pa /etc/protocols . .Bd -literal -offset indent .Pp struct protoent { char *p_name; /* official name of protocol */ char **p_aliases; /* alias list */ int p_proto; /* protocol number */ }; .Ed .Pp The members of this structure are: .Bl -tag -width p_aliases .It Fa p_name The official name of the protocol. .It Fa p_aliases A zero terminated list of alternate names for the protocol. .It Fa p_proto The protocol number. .El .Pp The .Fn getprotoent function reads the next line of the file, opening the file if necessary. .Pp The .Fn setprotoent function opens and rewinds the file. If the .Fa stayopen flag is non-zero, the net data base will not be closed after each call to .Fn getprotobyname or .Fn getprotobynumber . .Pp The .Fn endprotoent function closes the file. .Pp The .Fn getprotobyname function and .Fn getprotobynumber sequentially search from the beginning of the file until a matching protocol name or protocol number is found, or until .Dv EOF is encountered. .Sh RETURN VALUES Null pointer (0) returned on .Dv EOF or error. .Sh FILES .Bl -tag -width /etc/protocols -compact .It Pa /etc/protocols .El .Sh SEE ALSO .Xr protocols 5 .Sh HISTORY The .Fn getprotoent , .Fn getprotobynumber , .Fn getprotobyname , .Fn setprotoent , and .Fn endprotoent functions appeared in .Bx 4.2 . .Sh BUGS These functions use a static data space; if the data is needed for future use, it should be copied before any subsequent calls overwrite it. Only the Internet protocols are currently understood.