systemd/man/sd_session_is_active.xml
2011-12-19 14:42:59 +01:00

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<?xml version='1.0'?> <!--*-nxml-*-->
<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN"
"http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd">
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<refentry id="sd_session_is_active">
<refentryinfo>
<title>sd_session_is_active</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_session_is_active</refentrytitle>
<manvolnum>3</manvolnum>
</refmeta>
<refnamediv>
<refname>sd_session_is_active</refname>
<refname>sd_session_get_uid</refname>
<refname>sd_session_get_seat</refname>
<refpurpose>Determine state of a specific session</refpurpose>
</refnamediv>
<refsynopsisdiv>
<funcsynopsis>
<funcsynopsisinfo>#include &lt;systemd/sd-login.h&gt;</funcsynopsisinfo>
<funcprototype>
<funcdef>int <function>sd_session_is_active</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_uid</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>uid_t* <parameter>uid</parameter></paramdef>
</funcprototype>
<funcprototype>
<funcdef>int <function>sd_session_get_seat</function></funcdef>
<paramdef>const char* <parameter>session</parameter></paramdef>
<paramdef>char** <parameter>seat</parameter></paramdef>
</funcprototype>
</funcsynopsis>
</refsynopsisdiv>
<refsect1>
<title>Description</title>
<para><function>sd_session_is_active()</function> may
be used to determine whether the session identified by
the specified session identifier is currently active
(i.e. currently in the foreground and available for
user input) or not.</para>
<para><function>sd_session_get_uid()</function> may be
used to determine the user identifier of the Unix user the session
identified by the specified session identifier belongs
to.</para>
<para><function>sd_session_get_seat()</function> may
be used to determine the seat identifier of the seat
the session identified by the specified session
identifier belongs to. Note that not all sessions are
attached to a seat, this call will fail for them. The
returned string needs to be freed with the libc
<citerefentry><refentrytitle>free</refentrytitle><manvolnum>3</manvolnum></citerefentry>
call after use.</para>
</refsect1>
<refsect1>
<title>Return Value</title>
<para>If the test succeeds
<function>sd_session_is_active()</function> returns a
positive integer, if it fails 0. On success
<function>sd_session_get_uid()</function> and
<function>sd_session_get_seat()</function> return 0 or
a positive integer. On failure, these calls return a
negative errno-style error code.</para>
</refsect1>
<refsect1>
<title>Notes</title>
<para>The <function>sd_session_is_active()</function>,
<function>sd_session_get_uid()</function>, and
<function>sd_session_get_seat()</function> interfaces
are available as shared library, which can be compiled
and linked to with the
<literal>libsystemd-login</literal>
<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-login</refentrytitle><manvolnum>7</manvolnum></citerefentry>,
<citerefentry><refentrytitle>sd_pid_get_session</refentrytitle><manvolnum>3</manvolnum></citerefentry>
</para>
</refsect1>
</refentry>