Systemd/man/sd_journal_get_cutoff_realtime_usec.xml

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<refentry id="sd_journal_get_cutoff_realtime_usec">

        <refentryinfo>
                <title>sd_journal_get_cutoff_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_cutoff_realtime_usec</refentrytitle>
                <manvolnum>3</manvolnum>
        </refmeta>

        <refnamediv>
                <refname>sd_journal_get_cutoff_realtime_usec</refname>
                <refname>sd_journal_get_cutoff_monotonic_usec</refname>
                <refpurpose>Read cut-off 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_cutoff_realtime_usec</function></funcdef>
                                <paramdef>sd_journal *<parameter>j</parameter></paramdef>
                                <paramdef>uint64_t *<parameter>from</parameter></paramdef>
                                <paramdef>uint64_t *<parameter>to</parameter></paramdef>
                        </funcprototype>

                        <funcprototype>
                                <funcdef>int <function>sd_journal_get_cutoff_monotonic_usec</function></funcdef>
                                <paramdef>sd_journal *<parameter>j</parameter></paramdef>
                                <paramdef>sd_id128_t <parameter>boot_id</parameter></paramdef>
                                <paramdef>uint64_t *<parameter>from</parameter></paramdef>
                                <paramdef>uint64_t *<parameter>to</parameter></paramdef>
                        </funcprototype>

                </funcsynopsis>
        </refsynopsisdiv>

        <refsect1>
                <title>Description</title>

                <para><function>sd_journal_get_cutoff_realtime_usec()</function>
                retrieves the realtime (wallclock) timestamps of the
                first and last entries accessible in the journal.  It
                takes three arguments: the journal context object
                <parameter>j</parameter> and two pointers
                <parameter>from</parameter> and
                <parameter>to</parameter> pointing at 64-bit unsigned
                integers to store the timestamps in. The timestamps
                are in microseconds since the epoch,
                i.e. <constant>CLOCK_REALTIME</constant>. Either one
                of the two timestamp arguments may be passed as
                <constant>NULL</constant> in case the timestamp is not
                needed, but not both.</para>

                <para><function>sd_journal_get_cutoff_monotonic_usec()</function>
                retrieves the monotonic timestamps of the first and
                last entries accessible in the journal. It takes three
                arguments: the journal context object
                <parameter>j</parameter>, a 128-bit identifier for the
                boot <parameter>boot_id</parameter>, and two pointers
                to 64-bit unsigned integers to store the timestamps,
                <parameter>from</parameter> and
                <parameter>to</parameter>. The timestamps are 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. The function will return the
                timestamps for the boot identified by the passed boot
                ID. Either one of the two timestamp arguments may be
                passed as <constant>NULL</constant> in case the
                timestamp is not needed, but not both.</para>
        </refsect1>

        <refsect1>
                <title>Return Value</title>

                <para><function>sd_journal_get_cutoff_realtime_usec()</function>
                and
                <function>sd_journal_get_cutoff_monotonic_usec()</function>
                return 1 on success, 0 if not suitable entries are in
                the journal or a negative errno-style error code.</para>

                <para>Locations pointed to by parameters
                <parameter>from</parameter> and
                <parameter>to</parameter> will be set only if the
                return value is positive, and obviously, the
                parameters are non-null.</para>
        </refsect1>

        <refsect1>
                <title>Notes</title>

                <para>The
                <function>sd_journal_get_cutoff_realtime_usec()</function>
                and
                <function>sd_journal_get_cutoff_monotonic_usec()</function>
                interfaces are available as a shared library, which can
                be compiled and linked to with the
                <constant>libsystemd</constant> <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-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>sd_journal_open</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
                        <citerefentry><refentrytitle>sd_journal_get_realtime_usec</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>
                </para>
        </refsect1>

</refentry>