120 lines
4.4 KiB
XML
120 lines
4.4 KiB
XML
<?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">
|
||
|
||
<!--
|
||
SPDX-License-Identifier: LGPL-2.1+
|
||
|
||
This file is part of systemd.
|
||
|
||
Copyright 2012 Lennart Poettering
|
||
-->
|
||
|
||
<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. If <parameter>ret</parameter> is passed as NULL the
|
||
function will validate the passed ID string, but not actually return it in parsed form.</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>
|