units: simplify rescue.service and emergency.service (#5623)

[thirdparty/systemd.git] / man / sd_journal_has_runtime_files.xml

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<refentry id="sd_journal_has_runtime_files">

  <refentryinfo>
    <title>sd_journal_has_runtime_files</title>
    <productname>systemd</productname>

    <authorgroup>
      <author>
        <contrib>Developer</contrib>
        <firstname>Jan</firstname>
        <surname>Synáček</surname>
        <email>jan.synacek@gmail.com</email>
      </author>
    </authorgroup>
  </refentryinfo>

  <refmeta>
    <refentrytitle>sd_journal_has_runtime_files</refentrytitle>
    <manvolnum>3</manvolnum>
  </refmeta>

  <refnamediv>
    <refname>sd_journal_has_runtime_files</refname>
    <refname>sd_journal_has_persistent_files</refname>
    <refpurpose>Query availability of runtime or persistent journal files.</refpurpose>
  </refnamediv>

  <refsynopsisdiv>
    <funcsynopsis>
      <funcsynopsisinfo>#include &lt;systemd/sd-journal.h&gt;</funcsynopsisinfo>

      <funcprototype>
        <funcdef>int <function>sd_journal_has_runtime_files</function></funcdef>
        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
      </funcprototype>

      <funcprototype>
        <funcdef>int <function>sd_journal_has_persistent_files</function></funcdef>
        <paramdef>sd_journal *<parameter>j</parameter></paramdef>
      </funcprototype>

    </funcsynopsis>
  </refsynopsisdiv>

  <refsect1>
    <title>Description</title>

    <para><function>sd_journal_has_runtime_files()</function> returns a positive value
    if runtime journal files (present in /run/systemd/journal/) have been found.
    Otherwise returns 0.</para>

    <para><function>sd_journal_has_persistent_files()</function> returns a positive value
    if persistent journal files (present in /var/log/journal/) have been found.
    Otherwise returns 0.</para>
  </refsect1>

  <refsect1>
    <title>Return value</title>
    <para>Both <function>sd_journal_has_runtime_files()</function>
    and <function>sd_journal_has_persistent_files()</function> return -EINVAL
    if their argument is NULL.
    </para>
  </refsect1>

  <refsect1>
    <title>Notes</title>

    <para>All functions listed here are thread-agnostic and only a single thread may operate
    on a given <structname>sd_journal</structname> object.</para>

    <para>Functions listed here 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>sd-journal</refentrytitle><manvolnum>3</manvolnum></citerefentry>
    </para>
  </refsect1>

</refentry>