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1 | <?xml version='1.0'?> <!--*-nxml-*--> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
4 | ||
5 | <!-- | |
6 | This file is part of systemd. | |
7 | ||
8 | Copyright 2012 Lennart Poettering | |
9 | ||
10 | systemd is free software; you can redistribute it and/or modify it | |
11 | under the terms of the GNU Lesser General Public License as published by | |
12 | the Free Software Foundation; either version 2.1 of the License, or | |
13 | (at your option) any later version. | |
14 | ||
15 | systemd is distributed in the hope that it will be useful, but | |
16 | WITHOUT ANY WARRANTY; without even the implied warranty of | |
17 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
18 | Lesser General Public License for more details. | |
19 | ||
20 | You should have received a copy of the GNU Lesser General Public License | |
21 | along with systemd; If not, see <http://www.gnu.org/licenses/>. | |
22 | --> | |
23 | ||
24 | <refentry id="sd_id128_to_string"> | |
25 | ||
26 | <refentryinfo> | |
27 | <title>sd_id128_to_string</title> | |
28 | <productname>systemd</productname> | |
29 | ||
30 | <authorgroup> | |
31 | <author> | |
32 | <contrib>Developer</contrib> | |
33 | <firstname>Lennart</firstname> | |
34 | <surname>Poettering</surname> | |
35 | <email>lennart@poettering.net</email> | |
36 | </author> | |
37 | </authorgroup> | |
38 | </refentryinfo> | |
39 | ||
40 | <refmeta> | |
41 | <refentrytitle>sd_id128_to_string</refentrytitle> | |
42 | <manvolnum>3</manvolnum> | |
43 | </refmeta> | |
44 | ||
45 | <refnamediv> | |
46 | <refname>sd_id128_to_string</refname> | |
47 | <refname>sd_id128_from_string</refname> | |
14228c0d | 48 | <refpurpose>Format or parse 128-bit IDs as strings</refpurpose> |
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49 | </refnamediv> |
50 | ||
51 | <refsynopsisdiv> | |
52 | <funcsynopsis> | |
53 | <funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo> | |
54 | ||
55 | <funcprototype> | |
56 | <funcdef>char* <function>sd_id128_to_string</function></funcdef> | |
57 | <paramdef>sd_id128_t <parameter>id</parameter>, char <parameter>s</parameter>[33]</paramdef> | |
58 | </funcprototype> | |
59 | ||
60 | <funcprototype> | |
61 | <funcdef>int <function>sd_id128_from_string</function></funcdef> | |
62 | <paramdef>const char* <parameter>s</parameter>, sd_id128_t* <parameter>ret</parameter></paramdef> | |
63 | </funcprototype> | |
64 | ||
65 | </funcsynopsis> | |
66 | </refsynopsisdiv> | |
67 | ||
68 | <refsect1> | |
69 | <title>Description</title> | |
70 | ||
71 | <para><function>sd_id128_to_string()</function> | |
14228c0d | 72 | formats a 128-bit ID as a character string. It expects |
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73 | the ID and a string array capable of storing 33 |
74 | characters. The ID will be formatted as 32 lowercase | |
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75 | hexadecimal digits and be terminated by a |
76 | <constant>NUL</constant> byte.</para> | |
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77 | |
78 | <para><function>sd_id128_from_string()</function> | |
79 | implements the reverse operation: it takes a 33 | |
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80 | character string with 32 hexadecimal digits (either |
81 | lowercase or uppercase, terminated by | |
82 | <constant>NUL</constant>) and parses them back into a | |
83 | 128-bit ID returned in | |
663996b3 | 84 | <parameter>ret</parameter>. Alternatively, this call |
14228c0d | 85 | can also parse a 37-character string with a 128-bit ID |
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86 | formatted as RFC UUID.</para> |
87 | ||
88 | <para>For more information about the | |
89 | <literal>sd_id128_t</literal> type see | |
90 | <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Note | |
91 | that these calls operate the same way on all | |
92 | architectures, i.e. the results do not depend on | |
14228c0d | 93 | endianness.</para> |
663996b3 | 94 | |
14228c0d | 95 | <para>When formatting a 128-bit ID into a string, it is |
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96 | often easier to use a format string for |
97 | <citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This | |
98 | is easily done using the | |
99 | <function>SD_ID128_FORMAT_STR</function> and | |
100 | <function>SD_ID128_FORMAT_VAL()</function> macros. For | |
101 | more information see | |
102 | <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> | |
103 | </refsect1> | |
104 | ||
105 | <refsect1> | |
106 | <title>Return Value</title> | |
107 | ||
108 | <para><function>sd_id128_to_string()</function> always | |
109 | succeeds and returns a pointer to the string array | |
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110 | passed in. <function>sd_id128_from_string</function> |
111 | returns 0 on success, in which case | |
112 | <parameter>ret</parameter> is filled in, or a negative | |
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113 | errno-style error code.</para> |
114 | </refsect1> | |
115 | ||
116 | <refsect1> | |
117 | <title>Notes</title> | |
118 | ||
119 | <para>The <function>sd_id128_to_string()</function> | |
120 | and <function>sd_id128_from_string()</function> interfaces are | |
121 | available as shared library, which can be compiled and | |
14228c0d | 122 | linked to with the <literal>libsystemd-id128</literal> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry> |
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123 | file.</para> |
124 | </refsect1> | |
125 | ||
126 | <refsect1> | |
127 | <title>See Also</title> | |
128 | ||
129 | <para> | |
130 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
131 | <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
132 | <citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
133 | </para> | |
134 | </refsect1> | |
135 | ||
136 | </refentry> |