125 lines
3.4 KiB
HTML
125 lines
3.4 KiB
HTML
|
|
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
|
|
<HTML><HEAD><TITLE>Man page of SD_BUS_SLOT_SET_USERDATA</TITLE>
|
|
</HEAD><BODY>
|
|
<H1>SD_BUS_SLOT_SET_USERDATA</H1>
|
|
Section: sd_bus_slot_set_userdata (3)<BR>Updated: <BR><A HREF="#index">Index</A>
|
|
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
|
<A NAME="lbAB"> </A>
|
|
<H2>NAME</H2>
|
|
|
|
sd_bus_slot_set_userdata, sd_bus_slot_get_userdata - Set and query the value in the "userdata" field
|
|
<A NAME="lbAC"> </A>
|
|
<H2>SYNOPSIS</H2>
|
|
|
|
<P>
|
|
<B>
|
|
</B><PRE>
|
|
#include <<A HREF="file:///usr/include/systemd/sd-bus.h">systemd/sd-bus.h</A>>
|
|
</PRE>
|
|
|
|
|
|
<DL COMPACT>
|
|
<DT id="1">
|
|
<B>void* sd_bus_slot_set_userdata(sd_bus_slot* </B><I>slot</I><B>, void* </B><I>userdata</I><B>);</B>
|
|
|
|
<DT id="2">
|
|
<B>void* sd_bus_slot_get_userdata(sd_bus_slot* </B><I>slot</I><B>);</B>
|
|
|
|
</DL>
|
|
<A NAME="lbAD"> </A>
|
|
<H2>DESCRIPTION</H2>
|
|
|
|
<P>
|
|
|
|
<DD>The userdata pointer allows data to be passed between the point where a callback is registered, for example when a filter is added using
|
|
<B><A HREF="/cgi-bin/man/man2html?3+sd_bus_add_filter">sd_bus_add_filter</A></B>(3)
|
|
or an asynchronous function call is made using
|
|
<B><A HREF="/cgi-bin/man/man2html?3+sd_bus_call_async">sd_bus_call_async</A></B>(3), and the point where the callback is called, without having any global state. The pointer has type
|
|
<B>void*</B>
|
|
and is not used by the sd-bus functions in any way, except to pass to the callback function.
|
|
<P>
|
|
|
|
Usually, the userdata field is set when the slot object is initially registered.
|
|
<B>sd_bus_slot_set_userdata()</B>
|
|
may be used to change it later for the bus slot object
|
|
<I>slot</I>. Previous value of the field is returned. The argument and returned value may be
|
|
<B>NULL</B>. It will be passed as the
|
|
<I>userdata</I>
|
|
argument to the callback function attached to the slot.
|
|
<P>
|
|
|
|
<B>sd_bus_slot_set_userdata()</B>
|
|
gets the value of the userdata field in the bus slot object
|
|
<I>slot</I>.
|
|
<A NAME="lbAE"> </A>
|
|
<H2>RETURN VALUE</H2>
|
|
|
|
<P>
|
|
|
|
On success, these functions return the value of the userdata field before the function call. If the
|
|
<I>slot</I>
|
|
object is
|
|
<B>NULL</B>,
|
|
<B>NULL</B>
|
|
will be returned to signify an error, but this is not distinguishable from the userdata field value being
|
|
<B>NULL</B>.
|
|
<A NAME="lbAF"> </A>
|
|
<H2>NOTES</H2>
|
|
|
|
<P>
|
|
|
|
These APIs are implemented as a shared library, which can be compiled and linked to with the
|
|
<B>libsystemd</B> <B><A HREF="/cgi-bin/man/man2html?1+pkg-config">pkg-config</A></B>(1)
|
|
file.
|
|
<A NAME="lbAG"> </A>
|
|
<H2>SEE ALSO</H2>
|
|
|
|
<P>
|
|
|
|
<B><A HREF="/cgi-bin/man/man2html?1+systemd">systemd</A></B>(1),
|
|
<B><A HREF="/cgi-bin/man/man2html?3+sd-bus">sd-bus</A></B>(3),
|
|
<B><A HREF="/cgi-bin/man/man2html?3+sd_bus_slot_set_destroy_callback">sd_bus_slot_set_destroy_callback</A></B>(3),
|
|
<B><A HREF="/cgi-bin/man/man2html?3+sd_bus_add_match">sd_bus_add_match</A></B>(3),
|
|
<B><A HREF="/cgi-bin/man/man2html?3+sd_bus_slot_get_current_userdata">sd_bus_slot_get_current_userdata</A></B>(3)
|
|
<P>
|
|
|
|
<HR>
|
|
<A NAME="index"> </A><H2>Index</H2>
|
|
<DL>
|
|
<DT id="3"><A HREF="#lbAB">NAME</A><DD>
|
|
<DT id="4"><A HREF="#lbAC">SYNOPSIS</A><DD>
|
|
<DT id="5"><A HREF="#lbAD">DESCRIPTION</A><DD>
|
|
<DT id="6"><A HREF="#lbAE">RETURN VALUE</A><DD>
|
|
<DT id="7"><A HREF="#lbAF">NOTES</A><DD>
|
|
<DT id="8"><A HREF="#lbAG">SEE ALSO</A><DD>
|
|
</DL>
|
|
<HR>
|
|
This document was created by
|
|
<A HREF="/cgi-bin/man/man2html">man2html</A>,
|
|
using the manual pages.<BR>
|
|
Time: 00:05:55 GMT, March 31, 2021
|
|
</BODY>
|
|
</HTML>
|