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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
- "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
+ "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
<!--
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<refentry id="sd-id128"
- xmlns:xi="http://www.w3.org/2001/XInclude">
-
- <refentryinfo>
- <title>sd-id128</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</refentrytitle>
- <manvolnum>3</manvolnum>
- </refmeta>
-
- <refnamediv>
- <refname>sd-id128</refname>
- <refname>sd_id128_t</refname>
- <refname>SD_ID128_MAKE</refname>
- <refname>SD_ID128_CONST_STR</refname>
- <refname>SD_ID128_FORMAT_STR</refname>
- <refname>SD_ID128_FORMAT_VAL</refname>
- <refname>sd_id128_equal</refname>
- <refpurpose>APIs for processing 128-bit IDs</refpurpose>
- </refnamediv>
-
- <refsynopsisdiv>
- <funcsynopsis>
- <funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo>
- </funcsynopsis>
-
- <cmdsynopsis>
- <command>pkg-config --cflags --libs libsystemd</command>
- </cmdsynopsis>
-
- </refsynopsisdiv>
-
- <refsect1>
- <title>Description</title>
-
- <para><filename>sd-id128.h</filename> provides APIs to
- process and generate 128-bit ID values. The 128-bit ID
- values processed and generated by these APIs are a
- generalization of OSF UUIDs as defined by <ulink
- url="https://tools.ietf.org/html/rfc4122">RFC
- 4122</ulink> but use a simpler string
- format. These functions impose no structure on the
- used IDs, much unlike OSF UUIDs or Microsoft GUIDs,
- but are fully compatible with those types of IDs.
- </para>
-
- <para>See
- <citerefentry><refentrytitle>sd_id128_to_string</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry> and
- <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- for more information about the implemented
- functions.</para>
-
- <para>A 128-bit ID is implemented as the following
- union type:</para>
-
- <programlisting>typedef union sd_id128 {
- uint8_t bytes[16];
- uint64_t qwords[2];
+ xmlns:xi="http://www.w3.org/2001/XInclude">
+
+ <refentryinfo>
+ <title>sd-id128</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</refentrytitle>
+ <manvolnum>3</manvolnum>
+ </refmeta>
+
+ <refnamediv>
+ <refname>sd-id128</refname>
+ <refname>sd_id128_t</refname>
+ <refname>SD_ID128_MAKE</refname>
+ <refname>SD_ID128_CONST_STR</refname>
+ <refname>SD_ID128_FORMAT_STR</refname>
+ <refname>SD_ID128_FORMAT_VAL</refname>
+ <refname>sd_id128_equal</refname>
+ <refpurpose>APIs for processing 128-bit IDs</refpurpose>
+ </refnamediv>
+
+ <refsynopsisdiv>
+ <funcsynopsis>
+ <funcsynopsisinfo>#include <systemd/sd-id128.h></funcsynopsisinfo>
+ </funcsynopsis>
+
+ <cmdsynopsis>
+ <command>pkg-config --cflags --libs libsystemd</command>
+ </cmdsynopsis>
+
+ </refsynopsisdiv>
+
+ <refsect1>
+ <title>Description</title>
+
+ <para><filename>sd-id128.h</filename> provides APIs to process and
+ generate 128-bit ID values. The 128-bit ID values processed and
+ generated by these APIs are a generalization of OSF UUIDs as
+ defined by <ulink url="https://tools.ietf.org/html/rfc4122">RFC
+ 4122</ulink> but use a simpler string format. These functions
+ impose no structure on the used IDs, much unlike OSF UUIDs or
+ Microsoft GUIDs, but are fully compatible with those types of IDs.
+ </para>
+
+ <para>See
+ <citerefentry><refentrytitle>sd_id128_to_string</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ and
+ <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ for more information about the implemented functions.</para>
+
+ <para>A 128-bit ID is implemented as the following
+ union type:</para>
+
+ <programlisting>typedef union sd_id128 {
+ uint8_t bytes[16];
+ uint64_t qwords[2];
} sd_id128_t;</programlisting>
- <para>This union type allows accessing the 128-bit ID
- as 16 separate bytes or two 64-bit words. It is generally
- safer to access the ID components by their 8-bit array
- to avoid endianness issues. This union is intended to
- be passed call-by-value (as opposed to
- call-by-reference) and may be directly manipulated by
- clients.</para>
-
- <para>A couple of macros are defined to denote and
- decode 128-bit IDs:</para>
-
- <para><function>SD_ID128_MAKE()</function> may be used
- to denote a constant 128-bit ID in source code. A
- commonly used idiom is to assign a name to a 128-bit
- ID using this macro:</para>
-
- <programlisting>#define SD_MESSAGE_COREDUMP SD_ID128_MAKE(fc,2e,22,bc,6e,e6,47,b6,b9,07,29,ab,34,a2,50,b1)</programlisting>
-
- <para><function>SD_ID128_CONST_STR()</function> may be
- used to convert constant 128-bit IDs into constant
- strings for output. The following example code will
- output the string
- "fc2e22bc6ee647b6b90729ab34a250b1":</para>
- <programlisting>int main(int argc, char *argv[]) {
- puts(SD_ID128_CONST_STR(SD_MESSAGE_COREDUMP));
+ <para>This union type allows accessing the 128-bit ID as 16
+ separate bytes or two 64-bit words. It is generally safer to
+ access the ID components by their 8-bit array to avoid endianness
+ issues. This union is intended to be passed call-by-value (as
+ opposed to call-by-reference) and may be directly manipulated by
+ clients.</para>
+
+ <para>A couple of macros are defined to denote and decode 128-bit
+ IDs:</para>
+
+ <para><function>SD_ID128_MAKE()</function> may be used to denote a
+ constant 128-bit ID in source code. A commonly used idiom is to
+ assign a name to a 128-bit ID using this macro:</para>
+
+ <programlisting>#define SD_MESSAGE_COREDUMP SD_ID128_MAKE(fc,2e,22,bc,6e,e6,47,b6,b9,07,29,ab,34,a2,50,b1)</programlisting>
+
+ <para><function>SD_ID128_CONST_STR()</function> may be used to
+ convert constant 128-bit IDs into constant strings for output. The
+ following example code will output the string
+ "fc2e22bc6ee647b6b90729ab34a250b1":</para>
+ <programlisting>int main(int argc, char *argv[]) {
+ puts(SD_ID128_CONST_STR(SD_MESSAGE_COREDUMP));
}</programlisting>
- <para><function>SD_ID128_FORMAT_STR</function> and
- <function>SD_ID128_FORMAT_VAL()</function> may be used
- to format a 128-bit ID in a
- <citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
- format string, as shown in the following
- example:</para>
-
- <programlisting>int main(int argc, char *argv[]) {
- sd_id128_t id;
- id = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
- printf("The ID encoded in this C file is " SD_ID128_FORMAT_STR ".\n", SD_ID128_FORMAT_VAL(id));
- return 0;
+ <para><function>SD_ID128_FORMAT_STR</function> and
+ <function>SD_ID128_FORMAT_VAL()</function> may be used to format a
+ 128-bit ID in a
+ <citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>
+ format string, as shown in the following example:</para>
+
+ <programlisting>int main(int argc, char *argv[]) {
+ sd_id128_t id;
+ id = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
+ printf("The ID encoded in this C file is " SD_ID128_FORMAT_STR ".\n", SD_ID128_FORMAT_VAL(id));
+ return 0;
}</programlisting>
-
<para>Use <function>sd_id128_equal()</function> to compare two 128-bit IDs:</para>
+ <para>Use <function>sd_id128_equal()</function> to compare two 128-bit IDs:</para>
-
<programlisting>int main(int argc, char *argv[]) {
- sd_id128_t a, b, c;
- a = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
- b = SD_ID128_MAKE(f2,28,88,9c,5f,09,44,15,9d,d7,04,77,58,cb,e7,3e);
- c = a;
- assert(sd_id128_equal(a, c));
- assert(!sd_id128_equal(a, b));
- return 0;
+ <programlisting>int main(int argc, char *argv[]) {
+ sd_id128_t a, b, c;
+ a = SD_ID128_MAKE(ee,89,be,71,bd,6e,43,d6,91,e6,c5,5d,eb,03,02,07);
+ b = SD_ID128_MAKE(f2,28,88,9c,5f,09,44,15,9d,d7,04,77,58,cb,e7,3e);
+ c = a;
+ assert(sd_id128_equal(a, c));
+ assert(!sd_id128_equal(a, b));
+ return 0;
}</programlisting>
- <para>Note that new, randomized IDs may be generated
- with
- <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
- <option>--new-id</option> option.</para>
- </refsect1>
-
- <xi:include href="libsystemd-pkgconfig.xml" />
-
- <refsect1>
- <title>See Also</title>
- <para>
- <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_id128_to_string</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
- <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
- </para>
- </refsect1>
+ <para>Note that new, randomized IDs may be generated with
+ <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>'s
+ <option>--new-id</option> option.</para>
+ </refsect1>
+
+ <xi:include href="libsystemd-pkgconfig.xml" />
+
+ <refsect1>
+ <title>See Also</title>
+ <para>
+ <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_id128_to_string</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_id128_randomize</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd_id128_get_machine</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>journalctl</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>sd-journal</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
+ <citerefentry project='die-net'><refentrytitle>pkg-config</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
+ <citerefentry><refentrytitle>machine-id</refentrytitle><manvolnum>5</manvolnum></citerefentry>
+ </para>
+ </refsect1>
</refentry>
~ianmdlvl / elogind.git / blobdiff