- <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 218</span><hr><div class="refentry"><a name="sd_session_is_active"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_session_is_active, sd_session_is_remote, sd_session_get_state, sd_session_get_uid, sd_session_get_seat, sd_session_get_service, sd_session_get_type, sd_session_get_class, sd_session_get_desktop, sd_session_get_display, sd_session_get_tty, sd_session_get_vt, sd_session_get_remote_host, sd_session_get_remote_user — Determine state of a specific session</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include <systemd/sd-login.h></pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_is_active</b>(</code></td><td>const char *<var class="pdparam">session</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_is_remote</b>(</code></td><td>const char *<var class="pdparam">session</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_state</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">state</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_uid</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">uid</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_seat</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">seat</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_service</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">service</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_type</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">type</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_class</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">class</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_desktop</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">desktop</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_display</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">display</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_remote_host</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">remote_host</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_remote_user</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">remote_user</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_tty</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">tty</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_vt</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>unsigned int *<var class="pdparam">vt</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm140536242843936"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_session_is_active()</code> 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.</p><p><code class="function">sd_session_is_remote()</code> may
- be used to determine whether the session identified by
- the specified session identifier is a remote session
- (i.e. its remote host is known) or not.</p><p><code class="function">sd_session_get_state()</code> may
- be used to determine the state of the session
- identified by the specified session identifier. The
- following states are currently known:
- "<code class="literal">online</code>" (session logged in, but
- session not active, i.e. not in the foreground),
- "<code class="literal">active</code>" (session logged in and
- active, i.e. in the foreground),
- "<code class="literal">closing</code>" (session nominally logged
- out, but some processes belonging to it are still
- around). In the future additional states might be
- defined, client code should be written to be robust in
- regards to additional state strings being
- returned. This function is a more generic version of
- <code class="function">sd_session_is_active()</code>. The returned
- string needs to be freed with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_uid()</code> may be
- used to determine the user identifier of the Unix user the session
- identified by the specified session identifier belongs
- to.</p><p><code class="function">sd_session_get_seat()</code> 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
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_service()</code>
- may be used to determine the name of the service (as
- passed during PAM session setup) that registered the
- session identified by the specified session
- identifier. The returned string needs to be freed with
- the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_type()</code> may
- be used to determine the type of the session
- identified by the specified session identifier. The
- returned string is one of "<code class="literal">x11</code>",
- "<code class="literal">wayland</code>", "<code class="literal">tty</code>",
- "<code class="literal">mir</code>" or "<code class="literal">unspecified</code>" and
- needs to be freed with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_class()</code> may
- be used to determine the class of the session
- identified by the specified session identifier. The
- returned string is one of "<code class="literal">user</code>",
- "<code class="literal">greeter</code>",
- "<code class="literal">lock-screen</code>", or
- "<code class="literal">background</code>" and needs to be freed
- with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_desktop()</code> may
- be used to determine the brand of the desktop running on
- the session identified by the specified session identifier.
- This field can be set freely by desktop environments and
- does not follow any special formatting. However, desktops
- are strongly recommended to use the same identifiers and
- capitalization as for
- <code class="varname">$XDG_CURRENT_DESKTOP</code>, as defined by
- the <a class="ulink" href="http://standards.freedesktop.org/desktop-entry-spec/latest/" target="_top">Desktop
- Entry
- Specification</a>. The returned string needs to be
- freed with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_display()</code>
- may be used to determine the X11 display of the
- session identified by the specified session
- identifier. The returned string needs to be
- freed with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_remote_host()</code>
- may be used to determine the remote hostname of the
- session identified by the specified session
- identifier. The returned string needs to be
- freed with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_remote_user()</code>
- may be used to determine the remote username of the
- session identified by the specified session
- identifier. The returned string needs to be
- freed with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use. Note that this value is rarely known
- to the system, and even then should not be relied on.</p><p><code class="function">sd_session_get_tty()</code>
- may be used to determine the TTY device of the
- session identified by the specified session
- identifier. The returned string needs to be
- freed with the libc
- <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
- call after use.</p><p><code class="function">sd_session_get_vt()</code>
- may be used to determine the VT number of the
- session identified by the specified session
- identifier. This function will return an error if
- the seat does not support VTs.</p><p>If the <code class="varname">session</code> parameter of
- any of these functions is passed as
- <code class="constant">NULL</code>, the operation is executed
- for the session the calling process is a member of, if
- there is any.</p></div><div class="refsect1"><a name="idm140536237842848"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p>If the test succeeds,
- <code class="function">sd_session_is_active()</code> and
- <code class="function">sd_session_is_remote()</code> return a
- positive integer; if it fails, 0. On success,
- <code class="function">sd_session_get_state()</code>,
- <code class="function">sd_session_get_uid()</code>,
- <code class="function">sd_session_get_seat()</code>,
- <code class="function">sd_session_get_service()</code>,
- <code class="function">sd_session_get_type()</code>,
- <code class="function">sd_session_get_class()</code>,
- <code class="function">sd_session_get_display()</code>,
- <code class="function">sd_session_get_remote_user()</code>,
- <code class="function">sd_session_get_remote_host()</code> and
- <code class="function">sd_session_get_tty()</code> return 0 or
- a positive integer. On failure, these calls return a
- negative errno-style error code.</p></div><div class="refsect1"><a name="idm140536237833952"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p>The <code class="function">sd_session_is_active()</code>,
- <code class="function">sd_session_get_state()</code>,
- <code class="function">sd_session_get_uid()</code>,
- <code class="function">sd_session_get_seat()</code>,
- <code class="function">sd_session_get_service()</code>,
- <code class="function">sd_session_get_type()</code>,
- <code class="function">sd_session_get_class()</code>,
- <code class="function">sd_session_get_display()</code>,
- <code class="function">sd_session_get_remote_host()</code>,
- <code class="function">sd_session_get_remote_user()</code> and
- <code class="function">sd_session_get_tty()</code>
- interfaces are available as a shared library, which can
- be compiled and linked to with the
- <code class="constant">libsystemd</code> <a href="http://linux.die.net/man/1/pkg-config"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
- file.</p></div><div class="refsect1"><a name="idm140536237824384"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
- <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
- <a href="sd-login.html"><span class="citerefentry"><span class="refentrytitle">sd-login</span>(3)</span></a>,
- <a href="sd_pid_get_session.html"><span class="citerefentry"><span class="refentrytitle">sd_pid_get_session</span>(3)</span></a>
- </p></div></div></body></html>
+ <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 219</span><hr><div class="refentry"><a name="sd_session_is_active"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_session_is_active, sd_session_is_remote, sd_session_get_state, sd_session_get_uid, sd_session_get_seat, sd_session_get_service, sd_session_get_type, sd_session_get_class, sd_session_get_desktop, sd_session_get_display, sd_session_get_tty, sd_session_get_vt, sd_session_get_remote_host, sd_session_get_remote_user — Determine state of a specific session</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include <systemd/sd-login.h></pre><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_is_active</b>(</code></td><td>const char *<var class="pdparam">session</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_is_remote</b>(</code></td><td>const char *<var class="pdparam">session</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_state</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">state</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_uid</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>uid_t *<var class="pdparam">uid</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_seat</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">seat</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_service</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">service</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_type</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">type</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_class</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">class</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_desktop</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">desktop</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_display</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">display</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_remote_host</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">remote_host</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_remote_user</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">remote_user</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_tty</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>char **<var class="pdparam">tty</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div><table border="0" class="funcprototype-table" summary="Function synopsis" style="cellspacing: 0; cellpadding: 0;"><tr><td><code class="funcdef">int <b class="fsfunc">sd_session_get_vt</b>(</code></td><td>const char *<var class="pdparam">session</var>, </td></tr><tr><td> </td><td>unsigned int *<var class="pdparam">vt</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm140336054828912"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description">¶</a></h2><p><code class="function">sd_session_is_active()</code> 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.</p><p><code class="function">sd_session_is_remote()</code> may be used to
+ determine whether the session identified by the specified session
+ identifier is a remote session (i.e. its remote host is known) or
+ not.</p><p><code class="function">sd_session_get_state()</code> may be used to
+ determine the state of the session identified by the specified
+ session identifier. The following states are currently known:
+ "<code class="literal">online</code>" (session logged in, but session not
+ active, i.e. not in the foreground), "<code class="literal">active</code>"
+ (session logged in and active, i.e. in the foreground),
+ "<code class="literal">closing</code>" (session nominally logged out, but some
+ processes belonging to it are still around). In the future
+ additional states might be defined, client code should be written
+ to be robust in regards to additional state strings being
+ returned. This function is a more generic version of
+ <code class="function">sd_session_is_active()</code>. The returned string
+ needs to be freed with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_uid()</code> may be used to
+ determine the user identifier of the Unix user the session
+ identified by the specified session identifier belongs to.</p><p><code class="function">sd_session_get_seat()</code> 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
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_service()</code> may be used to
+ determine the name of the service (as passed during PAM session
+ setup) that registered the session identified by the specified
+ session identifier. The returned string needs to be freed with the
+ libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_type()</code> may be used to
+ determine the type of the session identified by the specified
+ session identifier. The returned string is one of
+ "<code class="literal">x11</code>", "<code class="literal">wayland</code>",
+ "<code class="literal">tty</code>", "<code class="literal">mir</code>" or
+ "<code class="literal">unspecified</code>" and needs to be freed with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_class()</code> may be used to
+ determine the class of the session identified by the specified
+ session identifier. The returned string is one of
+ "<code class="literal">user</code>", "<code class="literal">greeter</code>",
+ "<code class="literal">lock-screen</code>", or "<code class="literal">background</code>"
+ and needs to be freed with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_desktop()</code> may be used to
+ determine the brand of the desktop running on the session
+ identified by the specified session identifier. This field can be
+ set freely by desktop environments and does not follow any special
+ formatting. However, desktops are strongly recommended to use the
+ same identifiers and capitalization as for
+ <code class="varname">$XDG_CURRENT_DESKTOP</code>, as defined by the <a class="ulink" href="http://standards.freedesktop.org/desktop-entry-spec/latest/" target="_top">Desktop
+ Entry Specification</a>. The returned string needs to be freed
+ with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_display()</code> may be used to
+ determine the X11 display of the session identified by the
+ specified session identifier. The returned string needs to be
+ freed with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_remote_host()</code> may be
+ used to determine the remote hostname of the session identified by
+ the specified session identifier. The returned string needs to be
+ freed with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_remote_user()</code> may be
+ used to determine the remote username of the session identified by
+ the specified session identifier. The returned string needs to be
+ freed with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use. Note that this value is rarely known to the
+ system, and even then should not be relied on.</p><p><code class="function">sd_session_get_tty()</code> may be used to
+ determine the TTY device of the session identified by the
+ specified session identifier. The returned string needs to be
+ freed with the libc
+ <a href="http://man7.org/linux/man-pages/man3/free.3.html"><span class="citerefentry"><span class="refentrytitle">free</span>(3)</span></a>
+ call after use.</p><p><code class="function">sd_session_get_vt()</code> may be used to
+ determine the VT number of the session identified by the specified
+ session identifier. This function will return an error if the seat
+ does not support VTs.</p><p>If the <code class="varname">session</code> parameter of any of these
+ functions is passed as <code class="constant">NULL</code>, the operation is
+ executed for the session the calling process is a member of, if
+ there is any.</p></div><div class="refsect1"><a name="idm140336049877040"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value">¶</a></h2><p>If the test succeeds,
+ <code class="function">sd_session_is_active()</code> and
+ <code class="function">sd_session_is_remote()</code> return a
+ positive integer; if it fails, 0. On success,
+ <code class="function">sd_session_get_state()</code>,
+ <code class="function">sd_session_get_uid()</code>,
+ <code class="function">sd_session_get_seat()</code>,
+ <code class="function">sd_session_get_service()</code>,
+ <code class="function">sd_session_get_type()</code>,
+ <code class="function">sd_session_get_class()</code>,
+ <code class="function">sd_session_get_display()</code>,
+ <code class="function">sd_session_get_remote_user()</code>,
+ <code class="function">sd_session_get_remote_host()</code> and
+ <code class="function">sd_session_get_tty()</code> return 0 or
+ a positive integer. On failure, these calls return a
+ negative errno-style error code.</p></div><div class="refsect1"><a name="idm140336049868272"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes">¶</a></h2><p>The <code class="function">sd_session_is_active()</code>,
+ <code class="function">sd_session_get_state()</code>,
+ <code class="function">sd_session_get_uid()</code>,
+ <code class="function">sd_session_get_seat()</code>,
+ <code class="function">sd_session_get_service()</code>,
+ <code class="function">sd_session_get_type()</code>,
+ <code class="function">sd_session_get_class()</code>,
+ <code class="function">sd_session_get_display()</code>,
+ <code class="function">sd_session_get_remote_host()</code>,
+ <code class="function">sd_session_get_remote_user()</code> and
+ <code class="function">sd_session_get_tty()</code>
+ interfaces are available as a shared library, which can
+ be compiled and linked to with the
+ <code class="constant">libsystemd</code> <a href="http://linux.die.net/man/1/pkg-config"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
+ file.</p></div><div class="refsect1"><a name="idm140336049858736"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also">¶</a></h2><p>
+ <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
+ <a href="sd-login.html"><span class="citerefentry"><span class="refentrytitle">sd-login</span>(3)</span></a>,
+ <a href="sd_pid_get_session.html"><span class="citerefentry"><span class="refentrytitle">sd_pid_get_session</span>(3)</span></a>
+ </p></div></div></body></html>