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<refentry id="sd_journal_get_realtime_usec">

<refentryinfo>

<title>sd_journal_get_realtime_usec</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_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 &lt;systemd/sd-journal.h&gt;</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

in. 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, -ESTALE is returned by <function>sd_journal_get_monotonic_usec()</function>.</para>

</refsect1>

<refsect1>

<title>Notes</title>

<para>The

<function>sd_journal_get_realtime_usec()</function>

and

<function>sd_journal_get_monotonic_usec()</function>

interfaces are available as shared library, which can

be compiled and linked to with the

<constant>libsystemd-journal</constant>

<citerefentry><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-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>,

<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>

</refentry>