xref: /freebsd/lib/libc/net/getprotoent.3 (revision f3c5273d315a64826d2149ac453ff8c4583ddbe8)
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28.\"     @(#)getprotoent.3	8.1 (Berkeley) 6/4/93
29.\" $FreeBSD$
30.\"
31.Dd June 4, 1993
32.Dt GETPROTOENT 3
33.Os
34.Sh NAME
35.Nm getprotoent ,
36.Nm getprotobynumber ,
37.Nm getprotobyname ,
38.Nm setprotoent ,
39.Nm endprotoent
40.Nd get protocol entry
41.Sh LIBRARY
42.Lb libc
43.Sh SYNOPSIS
44.In netdb.h
45.Ft struct protoent *
46.Fn getprotoent void
47.Ft struct protoent *
48.Fn getprotobyname "const char *name"
49.Ft struct protoent *
50.Fn getprotobynumber "int proto"
51.Ft void
52.Fn setprotoent "int stayopen"
53.Ft void
54.Fn endprotoent void
55.Sh DESCRIPTION
56The
57.Fn getprotoent ,
58.Fn getprotobyname ,
59and
60.Fn getprotobynumber
61functions
62each return a pointer to an object with the
63following structure
64containing the broken-out
65fields of a line in the network protocol data base,
66.Pa /etc/protocols .
67.Bd -literal -offset indent
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.
94If the
95.Fa stayopen
96flag is non-zero,
97the net data base will not be closed after each call to
98.Fn getprotobyname
99or
100.Fn getprotobynumber .
101.Pp
102The
103.Fn endprotoent
104function
105closes the file.
106.Pp
107The
108.Fn getprotobyname
109function
110and
111.Fn getprotobynumber
112sequentially search from the beginning
113of the file until a matching
114protocol name or
115protocol number is found,
116or until
117.Dv EOF
118is encountered.
119.Sh RETURN VALUES
120Null pointer 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 thread-specific 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