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3b3d7d069d
Shift the asterisks in the documentation's prototypes such that they are consistent among each other. Use the right side to match what is used in source code. Addendum to commit v209~82.
137 lines
5.9 KiB
XML
137 lines
5.9 KiB
XML
<?xml version='1.0'?> <!--*-nxml-*-->
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!--
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This file is part of systemd.
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Copyright 2012 Lennart Poettering
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systemd is free software; you can redistribute it and/or modify it
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under the terms of the GNU Lesser General Public License as published by
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the Free Software Foundation; either version 2.1 of the License, or
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(at your option) any later version.
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systemd is distributed in the hope that it will be useful, but
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WITHOUT ANY WARRANTY; without even the implied warranty of
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MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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Lesser General Public License for more details.
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You should have received a copy of the GNU Lesser General Public License
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along with systemd; If not, see <http://www.gnu.org/licenses/>.
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-->
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<refentry id="sd_id128_to_string">
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<refentryinfo>
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<title>sd_id128_to_string</title>
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<productname>systemd</productname>
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<authorgroup>
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<author>
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<contrib>Developer</contrib>
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<firstname>Lennart</firstname>
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<surname>Poettering</surname>
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<email>lennart@poettering.net</email>
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</author>
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</authorgroup>
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</refentryinfo>
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<refmeta>
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<refentrytitle>sd_id128_to_string</refentrytitle>
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<manvolnum>3</manvolnum>
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</refmeta>
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<refnamediv>
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<refname>sd_id128_to_string</refname>
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<refname>sd_id128_from_string</refname>
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<refpurpose>Format or parse 128-bit IDs as strings</refpurpose>
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</refnamediv>
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<refsynopsisdiv>
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<funcsynopsis>
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<funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo>
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<funcprototype>
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<funcdef>char *<function>sd_id128_to_string</function></funcdef>
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<paramdef>sd_id128_t <parameter>id</parameter>, char <parameter>s</parameter>[33]</paramdef>
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</funcprototype>
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<funcprototype>
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<funcdef>int <function>sd_id128_from_string</function></funcdef>
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<paramdef>const char *<parameter>s</parameter>, sd_id128_t *<parameter>ret</parameter></paramdef>
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</funcprototype>
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</funcsynopsis>
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</refsynopsisdiv>
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<refsect1>
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<title>Description</title>
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<para><function>sd_id128_to_string()</function>
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formats a 128-bit ID as a character string. It expects
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the ID and a string array capable of storing 33
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characters. The ID will be formatted as 32 lowercase
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hexadecimal digits and be terminated by a
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<constant>NUL</constant> byte.</para>
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<para><function>sd_id128_from_string()</function>
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implements the reverse operation: it takes a 33
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character string with 32 hexadecimal digits (either
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lowercase or uppercase, terminated by
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<constant>NUL</constant>) and parses them back into a
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128-bit ID returned in
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<parameter>ret</parameter>. Alternatively, this call
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can also parse a 37-character string with a 128-bit ID
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formatted as RFC UUID.</para>
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<para>For more information about the
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<literal>sd_id128_t</literal> type see
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<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>. Note
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that these calls operate the same way on all
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architectures, i.e. the results do not depend on
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endianness.</para>
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<para>When formatting a 128-bit ID into a string, it is
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often easier to use a format string for
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<citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>. This
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is easily done using the
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<function>SD_ID128_FORMAT_STR</function> and
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<function>SD_ID128_FORMAT_VAL()</function> macros. For
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more information see
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<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>.</para>
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</refsect1>
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<refsect1>
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<title>Return Value</title>
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<para><function>sd_id128_to_string()</function> always
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succeeds and returns a pointer to the string array
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passed in. <function>sd_id128_from_string</function>
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returns 0 on success, in which case
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<parameter>ret</parameter> is filled in, or a negative
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errno-style error code.</para>
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</refsect1>
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<refsect1>
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<title>Notes</title>
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<para>The <function>sd_id128_to_string()</function>
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and <function>sd_id128_from_string()</function> interfaces are
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available as a shared library, which can be compiled and
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linked to with the <literal>libsystemd</literal> <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>
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file.</para>
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</refsect1>
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<refsect1>
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<title>See Also</title>
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<para>
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<citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sd-id128</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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</para>
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</refsect1>
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</refentry>
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