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< !DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<!-- SPDX - License - Identifier: LGPL - 2.1 - or - later -->
2012-07-13 21:32:11 +04:00
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<refentry id= "sd_journal_get_realtime_usec"
xmlns:xi="http://www.w3.org/2001/XInclude">
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<refentryinfo >
<title > sd_journal_get_realtime_usec</title>
<productname > systemd</productname>
</refentryinfo>
<refmeta >
<refentrytitle > sd_journal_get_realtime_usec</refentrytitle>
<manvolnum > 3</manvolnum>
</refmeta>
<refnamediv >
<refname > sd_journal_get_realtime_usec</refname>
<refname > sd_journal_get_monotonic_usec</refname>
<refpurpose > Read timestamps from the current journal entry</refpurpose>
</refnamediv>
<refsynopsisdiv >
<funcsynopsis >
<funcsynopsisinfo > #include < systemd/sd-journal.h> </funcsynopsisinfo>
<funcprototype >
<funcdef > int <function > sd_journal_get_realtime_usec</function> </funcdef>
<paramdef > sd_journal *<parameter > j</parameter> </paramdef>
<paramdef > uint64_t *<parameter > usec</parameter> </paramdef>
</funcprototype>
<funcprototype >
<funcdef > int <function > sd_journal_get_monotonic_usec</function> </funcdef>
<paramdef > sd_journal *<parameter > j</parameter> </paramdef>
<paramdef > uint64_t *<parameter > usec</parameter> </paramdef>
<paramdef > sd_id128_t *<parameter > boot_id</parameter> </paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1 >
<title > Description</title>
<para > <function > sd_journal_get_realtime_usec()</function> gets the
realtime (wallclock) timestamp of the current journal entry. It
takes two arguments: the journal context object and a pointer to a
64-bit unsigned integer to store the timestamp in. The timestamp
is in microseconds since the epoch, i.e.
<constant > CLOCK_REALTIME</constant> .</para>
<para > <function > sd_journal_get_monotonic_usec()</function> gets
the monotonic timestamp of the current journal entry. It takes
three arguments: the journal context object, a pointer to a 64-bit
unsigned integer to store the timestamp in, as well as a 128-bit
ID buffer to store the boot ID of the monotonic timestamp. The
timestamp is in microseconds since boot-up of the specific boot,
i.e. <constant > CLOCK_MONOTONIC</constant> . Since the monotonic
clock begins new with every reboot, it only defines a well-defined
point in time when used together with an identifier identifying
the boot. See
<citerefentry > <refentrytitle > sd_id128_get_boot</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry>
for more information. If the boot ID parameter is passed
<constant > NULL</constant> , the function will fail if the monotonic
timestamp of the current entry is not of the current system
boot.</para>
<para > Note that these functions will not work before
<citerefentry > <refentrytitle > sd_journal_next</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry>
(or related call) has been called at least
once, in order to position the read pointer at a valid entry.</para>
</refsect1>
<refsect1 >
<title > Return Value</title>
<para > <function > sd_journal_get_realtime_usec()</function> and
<function > sd_journal_get_monotonic_usec()</function> returns 0 on
success or a negative errno-style error code. If the boot ID
parameter was passed <constant > NULL</constant> and the monotonic
timestamp of the current journal entry is not of the current
system boot, <constant > -ESTALE</constant> is returned by
<function > sd_journal_get_monotonic_usec()</function> .</para>
</refsect1>
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<refsect1 >
<title > Notes</title>
<xi:include href= "threads-aware.xml" xpointer= "strict" />
<xi:include href= "libsystemd-pkgconfig.xml" xpointer= "pkgconfig-text" />
</refsect1>
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<refsect1 >
<title > See Also</title>
<para >
<citerefentry > <refentrytitle > systemd</refentrytitle> <manvolnum > 1</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > sd-journal</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > sd_journal_open</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > sd_journal_next</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > sd_journal_get_data</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
2023-01-26 13:04:44 +03:00
<citerefentry > <refentrytitle > sd_journal_get_seqnum</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
2015-02-04 05:14:13 +03:00
<citerefentry > <refentrytitle > sd_id128_get_boot</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > clock_gettime</refentrytitle> <manvolnum > 2</manvolnum> </citerefentry> ,
<citerefentry > <refentrytitle > sd_journal_get_cutoff_realtime_usec</refentrytitle> <manvolnum > 3</manvolnum> </citerefentry>
</para>
</refsect1>
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</refentry>