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12355095 | 1 | <?xml version='1.0'?> <!--*-nxml-*--> |
3a54a157 | 2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN" |
12b42c76 | 3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> |
0307f791 | 4 | <!-- SPDX-License-Identifier: LGPL-2.1+ --> |
12355095 | 5 | |
7d6b2723 | 6 | <refentry id="sd_id128_to_string" xmlns:xi="http://www.w3.org/2001/XInclude"> |
12355095 | 7 | |
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8 | <refentryinfo> |
9 | <title>sd_id128_to_string</title> | |
10 | <productname>systemd</productname> | |
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11 | </refentryinfo> |
12 | ||
13 | <refmeta> | |
14 | <refentrytitle>sd_id128_to_string</refentrytitle> | |
15 | <manvolnum>3</manvolnum> | |
16 | </refmeta> | |
17 | ||
18 | <refnamediv> | |
19 | <refname>sd_id128_to_string</refname> | |
20 | <refname>sd_id128_from_string</refname> | |
21 | <refpurpose>Format or parse 128-bit IDs as strings</refpurpose> | |
22 | </refnamediv> | |
23 | ||
24 | <refsynopsisdiv> | |
25 | <funcsynopsis> | |
26 | <funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo> | |
27 | ||
28 | <funcprototype> | |
29 | <funcdef>char *<function>sd_id128_to_string</function></funcdef> | |
30 | <paramdef>sd_id128_t <parameter>id</parameter>, char <parameter>s</parameter>[33]</paramdef> | |
31 | </funcprototype> | |
32 | ||
33 | <funcprototype> | |
34 | <funcdef>int <function>sd_id128_from_string</function></funcdef> | |
35 | <paramdef>const char *<parameter>s</parameter>, sd_id128_t *<parameter>ret</parameter></paramdef> | |
36 | </funcprototype> | |
37 | ||
38 | </funcsynopsis> | |
39 | </refsynopsisdiv> | |
40 | ||
41 | <refsect1> | |
42 | <title>Description</title> | |
43 | ||
44 | <para><function>sd_id128_to_string()</function> formats a 128-bit | |
45 | ID as a character string. It expects the ID and a string array | |
46 | capable of storing 33 characters. The ID will be formatted as 32 | |
47 | lowercase hexadecimal digits and be terminated by a | |
48 | <constant>NUL</constant> byte.</para> | |
49 | ||
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50 | <para><function>sd_id128_from_string()</function> implements the reverse operation: it takes a 33 character string |
51 | with 32 hexadecimal digits (either lowercase or uppercase, terminated by <constant>NUL</constant>) and parses them | |
52 | back into a 128-bit ID returned in <parameter>ret</parameter>. Alternatively, this call can also parse a | |
53 | 37-character string with a 128-bit ID formatted as RFC UUID. If <parameter>ret</parameter> is passed as NULL the | |
54 | function will validate the passed ID string, but not actually return it in parsed form.</para> | |
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55 | |
56 | <para>For more information about the <literal>sd_id128_t</literal> | |
57 | type see | |
58 | <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
59 | Note that these calls operate the same way on all architectures, | |
60 | i.e. the results do not depend on endianness.</para> | |
61 | ||
62 | <para>When formatting a 128-bit ID into a string, it is often | |
63 | easier to use a format string for | |
64 | <citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
65 | This is easily done using the | |
66 | <function>SD_ID128_FORMAT_STR</function> and | |
67 | <function>SD_ID128_FORMAT_VAL()</function> macros. For more | |
68 | information see | |
69 | <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para> | |
70 | </refsect1> | |
71 | ||
72 | <refsect1> | |
73 | <title>Return Value</title> | |
74 | ||
75 | <para><function>sd_id128_to_string()</function> always succeeds | |
76 | and returns a pointer to the string array passed in. | |
77 | <function>sd_id128_from_string</function> returns 0 on success, in | |
78 | which case <parameter>ret</parameter> is filled in, or a negative | |
79 | errno-style error code.</para> | |
80 | </refsect1> | |
81 | ||
7d6b2723 | 82 | <xi:include href="libsystemd-pkgconfig.xml" /> |
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83 | |
84 | <refsect1> | |
85 | <title>See Also</title> | |
86 | ||
87 | <para> | |
88 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
89 | <citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>, | |
90 | <citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
91 | </para> | |
92 | </refsect1> | |
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93 | |
94 | </refentry> |