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