1.\" Copyright (c) 1983, 1991, 1993 2.\" The Regents of the University of California. All rights reserved. 3.\" 4.\" %sccs.include.redist.man% 5.\" 6.\" @(#)getprotoent.3 8.1 (Berkeley) 06/04/93 7.\" 8.Dd 9.Dt GETPROTOENT 3 10.Os BSD 4.2 11.Sh NAME 12.Nm getprotoent , 13.Nm getprotobynumber , 14.Nm getprotobyname , 15.Nm setprotoent , 16.Nm endprotoent 17.Nd get protocol entry 18.Sh SYNOPSIS 19.Fd #include <netdb.h> 20.Ft struct protoent * 21.Fn getprotoent 22.Ft struct protoent * 23.Fn getprotobyname "char *name" 24.Ft struct protoent * 25.Fn getprotobynumber "int proto" 26.Fn setprotoent "int stayopen" 27.Fn endprotoent 28.Sh DESCRIPTION 29The 30.Fn getprotoent , 31.Fn getprotobyname , 32and 33.Fn getprotobynumber 34functions 35each return a pointer to an object with the 36following structure 37containing the broken-out 38fields of a line in the network protocol data base, 39.Pa /etc/protocols . 40.Bd -literal -offset indent 41.Pp 42struct protoent { 43 char *p_name; /* official name of protocol */ 44 char **p_aliases; /* alias list */ 45 int p_proto; /* protocol number */ 46}; 47.Ed 48.Pp 49The members of this structure are: 50.Bl -tag -width p_aliases 51.It Fa p_name 52The official name of the protocol. 53.It Fa p_aliases 54A zero terminated list of alternate names for the protocol. 55.It Fa p_proto 56The protocol number. 57.El 58.Pp 59The 60.Fn getprotoent 61function 62reads the next line of the file, opening the file if necessary. 63.Pp 64The 65.Fn setprotoent 66function 67opens and rewinds the file. If the 68.Fa stayopen 69flag is non-zero, 70the net data base will not be closed after each call to 71.Fn getprotobyname 72or 73.Fn getprotobynumber . 74.Pp 75The 76.Fn endprotoent 77function 78closes the file. 79.Pp 80The 81.Fn getprotobyname 82function 83and 84.Fn getprotobynumber 85sequentially search from the beginning 86of the file until a matching 87protocol name or 88protocol number is found, 89or until 90.Dv EOF 91is encountered. 92.Sh RETURN VALUES 93Null pointer 94(0) returned on 95.Dv EOF 96or error. 97.Sh FILES 98.Bl -tag -width /etc/protocols -compact 99.It Pa /etc/protocols 100.El 101.Sh SEE ALSO 102.Xr protocols 5 103.Sh HISTORY 104The 105.Fn getprotoent , 106.Fn getprotobynumber , 107.Fn getprotobyname , 108.Fn setprotoent , 109and 110.Fn endprotoent 111functions appeared in 112.Bx 4.2 . 113.Sh BUGS 114These functions use a static data space; 115if the data is needed for future use, it should be 116copied before any subsequent calls overwrite it. 117Only the Internet 118protocols are currently understood. 119