xref: /dragonfly/lib/libc/net/getprotoent.3 (revision 5e83d98b) 
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28.\"     @(#)getprotoent.3	8.1 (Berkeley) 6/4/93
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31.Dd May 4, 2019
32.Dt GETPROTOENT 3
33.Os
34.Sh NAME
35.Nm getprotoent ,
36.Nm getprotoent_r ,
37.Nm getprotobynumber ,
38.Nm getprotobynumber_r ,
39.Nm getprotobyname ,
40.Nm getprotobyname_r ,
41.Nm setprotoent ,
42.Nm endprotoent
43.Nd get protocol entry
44.Sh LIBRARY
45.Lb libc
46.Sh SYNOPSIS
47.In netdb.h
48.Ft struct protoent *
49.Fn getprotoent void
50.Ft int
51.Fn getprotoent_r "struct protoent *" "char *" "size_t" "struct protoent **"
52.Ft struct protoent *
53.Fn getprotobyname "const char *name"
54.Ft int
55.Fn getprotobyname_r "const char *" "struct protoent *" "char *" "size_t" "struct protoent **"
56.Ft struct protoent *
57.Fn getprotobynumber "int proto"
58.Ft int
59.Fn getprotobynumber_r "int" "struct protoent *" "char *" "size_t" "struct protoent **"
60.Ft void
61.Fn setprotoent "int stayopen"
62.Ft void
63.Fn endprotoent void
64.Sh DESCRIPTION
65The
66.Fn getprotoent ,
67.Fn getprotobyname ,
68and
69.Fn getprotobynumber
70functions
71each return a pointer to an object with the
72following structure
73containing the broken-out
74fields of a line in the network protocol data base,
75.Pa /etc/protocols .
76.Bd -literal -offset indent
77struct	protoent {
78	char	*p_name;	/* official name of protocol */
79	char	**p_aliases;	/* alias list */
80	int	p_proto;	/* protocol number */
81};
82.Ed
83.Pp
84The members of this structure are:
85.Bl -tag -width p_aliases
86.It Fa p_name
87The official name of the protocol.
88.It Fa p_aliases
89A zero terminated list of alternate names for the protocol.
90.It Fa p_proto
91The protocol number.
92.El
93.Pp
94The
95.Fn getprotoent
96function
97reads the next line of the file, opening the file if necessary.
98.Pp
99The
100.Fn setprotoent
101function
102opens and rewinds the file.
103If the
104.Fa stayopen
105flag is non-zero,
106the net data base will not be closed after each call to
107.Fn getprotobyname
108or
109.Fn getprotobynumber .
110.Pp
111The
112.Fn endprotoent
113function
114closes the file.
115.Pp
116The
117.Fn getprotobyname
118function
119and
120.Fn getprotobynumber
121sequentially search from the beginning
122of the file until a matching
123protocol name or
124protocol number is found,
125or until
126.Dv EOF
127is encountered.
128.Pp
129The
130.Fn getprotoent_r ,
131.Fn getprotobynumber_r ,
132and
133.Fn getprotobyname_r
134functions are reentrant versions of the above functions that take a
135pointer to a
136.Vt protoent
137structure which is used to store state information.
138The structure must be zero-filled before it is used
139and should be considered opaque for the sake of portability.
140These functions also take a pointer to another
141.Vt protoent
142structure which is used to store the results of the database lookup.
143.Sh RETURN VALUES
144The
145.Fn getprotoent ,
146.Fn getprotobynumber ,
147and
148.Fn getprotobyname
149functions return a pointer to a
150.Vt protoent
151structure on success or a null pointer if end-of-file
152is reached or an error occurs.
153.Pp
154The
155.Fn getprotoent_r ,
156.Fn getprotobynumber_r ,
157and
158.Fn getprotobyname_r
159functions return 0 on success or \-1 if end-of-file
160is reached or an error occurs.
161.Sh FILES
162.Bl -tag -width ".Pa /etc/protocols" -compact
163.It Pa /etc/protocols
164.El
165.Sh SEE ALSO
166.Xr protocols 5
167.Sh STANDARDS
168The
169.Fn getprotoent ,
170.Fn getprotobynumber ,
171.Fn getprotobyname ,
172.Fn setprotoent ,
173and
174.Fn endprotoent
175functions conform to
176.St -p1003.1-2004 .
177.Pp
178The
179.Fn getprotoent_r ,
180.Fn getprotobynumber_r ,
181and
182.Fn getprotobyname_r
183functions are not currently standardized.
184.Sh HISTORY
185The
186.Fn getprotoent ,
187.Fn getprotobynumber ,
188.Fn getprotobyname ,
189.Fn setprotoent ,
190and
191.Fn endprotoent
192functions appeared in
193.Bx 4.2 .
194.Pp
195The
196.Fn getprotoent_r ,
197.Fn getprotobynumber_r ,
198and
199.Fn getprotobyname_r
200functions appeared in
201.Dx 2.1 .
202.Sh BUGS
203These functions use a thread-specific data space;
204if the data is needed for future use, it should be
205copied before any subsequent calls overwrite it.
206Only the Internet
207protocols are currently understood.
208