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1 | .\" Copyright 1993 David Metcalfe (david@prism.demon.co.uk) |
2 | .\" | |
93015253 | 3 | .\" %%%LICENSE_START(VERBATIM) |
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4 | .\" Permission is granted to make and distribute verbatim copies of this |
5 | .\" manual provided the copyright notice and this permission notice are | |
6 | .\" preserved on all copies. | |
7 | .\" | |
8 | .\" Permission is granted to copy and distribute modified versions of this | |
9 | .\" manual under the conditions for verbatim copying, provided that the | |
10 | .\" entire resulting derived work is distributed under the terms of a | |
11 | .\" permission notice identical to this one. | |
c13182ef | 12 | .\" |
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13 | .\" Since the Linux kernel and libraries are constantly changing, this |
14 | .\" manual page may be incorrect or out-of-date. The author(s) assume no | |
15 | .\" responsibility for errors or omissions, or for damages resulting from | |
16 | .\" the use of the information contained herein. The author(s) may not | |
17 | .\" have taken the same level of care in the production of this manual, | |
18 | .\" which is licensed free of charge, as they might when working | |
19 | .\" professionally. | |
c13182ef | 20 | .\" |
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21 | .\" Formatted or processed versions of this manual, if unaccompanied by |
22 | .\" the source, must acknowledge the copyright and authors of this work. | |
4b72fb64 | 23 | .\" %%%LICENSE_END |
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24 | .\" |
25 | .\" References consulted: | |
26 | .\" Linux libc source code | |
27 | .\" Lewine's _POSIX Programmer's Guide_ (O'Reilly & Associates, 1991) | |
28 | .\" 386BSD man pages | |
29 | .\" Modified Sat Jul 24 21:48:06 1993 by Rik Faith (faith@cs.unc.edu) | |
4b8c67d9 | 30 | .TH GETNETENT 3 2017-09-15 "GNU" "Linux Programmer's Manual" |
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31 | .SH NAME |
32 | getnetent, getnetbyname, getnetbyaddr, setnetent, endnetent \- | |
c13182ef | 33 | get network entry |
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34 | .SH SYNOPSIS |
35 | .nf | |
36 | .B #include <netdb.h> | |
68e4db0a | 37 | .PP |
fea681da | 38 | .B struct netent *getnetent(void); |
68e4db0a | 39 | .PP |
fea681da | 40 | .BI "struct netent *getnetbyname(const char *" name ); |
68e4db0a | 41 | .PP |
15c15ebd | 42 | .BI "struct netent *getnetbyaddr(uint32_t " net ", int " type ); |
68e4db0a | 43 | .PP |
fea681da | 44 | .BI "void setnetent(int " stayopen ); |
68e4db0a | 45 | .PP |
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46 | .B void endnetent(void); |
47 | .fi | |
48 | .SH DESCRIPTION | |
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49 | The |
50 | .BR getnetent () | |
8dea53c5 | 51 | function reads the next entry from the networks database |
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52 | and returns a |
53 | .I netent | |
54 | structure containing | |
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55 | the broken-out fields from the entry. |
56 | A connection is opened to the database if necessary. | |
fea681da | 57 | .PP |
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58 | The |
59 | .BR getnetbyname () | |
c6fa0841 MK |
60 | function returns a |
61 | .I netent | |
62 | structure | |
8dea53c5 | 63 | for the entry from the database |
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64 | that matches the network |
65 | .IR name . | |
fea681da | 66 | .PP |
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67 | The |
68 | .BR getnetbyaddr () | |
c6fa0841 MK |
69 | function returns a |
70 | .I netent | |
71 | structure | |
8dea53c5 | 72 | for the entry from the database |
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73 | that matches the network number |
74 | .I net | |
75 | of type | |
76 | .IR type . | |
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77 | The |
78 | .I net | |
79 | argument must be in host byte order. | |
fea681da | 80 | .PP |
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81 | The |
82 | .BR setnetent () | |
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83 | function opens a connection to the database, |
84 | and sets the next entry to the first entry. | |
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85 | If |
86 | .I stayopen | |
87 | is nonzero, | |
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88 | then the connection to the database |
89 | will not be closed between calls to one of the | |
90 | .BR getnet* () | |
91 | functions. | |
fea681da | 92 | .PP |
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93 | The |
94 | .BR endnetent () | |
8dea53c5 | 95 | function closes the connection to the database. |
fea681da | 96 | .PP |
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97 | The |
98 | .I netent | |
99 | structure is defined in | |
100 | .I <netdb.h> | |
101 | as follows: | |
51f5698d | 102 | .PP |
a08ea57c | 103 | .in +4n |
b8302363 | 104 | .EX |
fea681da | 105 | struct netent { |
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106 | char *n_name; /* official network name */ |
107 | char **n_aliases; /* alias list */ | |
108 | int n_addrtype; /* net address type */ | |
109 | uint32_t n_net; /* network number */ | |
fea681da | 110 | } |
b8302363 | 111 | .EE |
a08ea57c | 112 | .in |
fea681da | 113 | .PP |
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114 | The members of the |
115 | .I netent | |
116 | structure are: | |
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117 | .TP |
118 | .I n_name | |
119 | The official name of the network. | |
120 | .TP | |
121 | .I n_aliases | |
8dea53c5 | 122 | A NULL-terminated list of alternative names for the network. |
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123 | .TP |
124 | .I n_addrtype | |
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125 | The type of the network number; always |
126 | .BR AF_INET . | |
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127 | .TP |
128 | .I n_net | |
129 | The network number in host byte order. | |
47297adb | 130 | .SH RETURN VALUE |
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131 | The |
132 | .BR getnetent (), | |
133 | .BR getnetbyname () | |
134 | and | |
135 | .BR getnetbyaddr () | |
d285b8b3 | 136 | functions return a pointer to a |
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137 | statically allocated |
138 | .I netent | |
b437fdd9 | 139 | structure, or a null pointer if an |
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140 | error occurs or the end of the file is reached. |
141 | .SH FILES | |
142 | .TP | |
143 | .I /etc/networks | |
144 | networks database file | |
d476c631 ZL |
145 | .SH ATTRIBUTES |
146 | For an explanation of the terms used in this section, see | |
147 | .BR attributes (7). | |
148 | .TS | |
149 | allbox; | |
150 | lbw14 lb lbw25 | |
151 | l l l. | |
152 | Interface Attribute Value | |
153 | T{ | |
154 | .BR getnetent () | |
155 | T} Thread safety T{ | |
156 | MT-Unsafe race:netent | |
157 | .br | |
158 | race:netentbuf env locale | |
159 | T} | |
160 | T{ | |
161 | .BR getnetbyname () | |
162 | T} Thread safety T{ | |
163 | MT-Unsafe race:netbyname | |
164 | .br | |
165 | env locale | |
166 | T} | |
167 | T{ | |
168 | .BR getnetbyaddr () | |
169 | T} Thread safety T{ | |
170 | MT-Unsafe race:netbyaddr | |
171 | .br | |
172 | locale | |
173 | T} | |
174 | T{ | |
175 | .BR setnetent (), | |
176 | .br | |
177 | .BR endnetent () | |
178 | T} Thread safety T{ | |
179 | MT-Unsafe race:netent env | |
180 | .br | |
181 | locale | |
182 | T} | |
183 | .TE | |
847e0d88 | 184 | .sp 1 |
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185 | In the above table, |
186 | .I netent | |
187 | in | |
188 | .I race:netent | |
189 | signifies that if any of the functions | |
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190 | .BR setnetent (), |
191 | .BR getnetent (), | |
d476c631 | 192 | or |
bf7bc8b8 | 193 | .BR endnetent () |
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194 | are used in parallel in different threads of a program, |
195 | then data races could occur. | |
47297adb | 196 | .SH CONFORMING TO |
dfac2a0a | 197 | POSIX.1-2001, POSIX.1-2008, 4.3BSD. |
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198 | .SH NOTES |
199 | In glibc versions before 2.2, the | |
200 | .I net | |
201 | argument of | |
202 | .BR getnetbyaddr () | |
203 | was of type | |
204 | .IR long . | |
47297adb | 205 | .SH SEE ALSO |
d285b8b3 | 206 | .BR getnetent_r (3), |
fea681da | 207 | .BR getprotoent (3), |
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208 | .BR getservent (3) |
209 | .\" .BR networks (5) | |
fea681da | 210 | .br |
331da7c3 | 211 | RFC\ 1101 |