man-pages/man3/sd_bus_message_get_signature.3.html
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<H1>SD_BUS_MESSAGE_GET_SIGNATURE</H1>
Section: sd_bus_message_get_signature (3)<BR>Updated: <BR><A HREF="#index">Index</A>
<A HREF="/cgi-bin/man/man2html">Return to Main Contents</A><HR>
<A NAME="lbAB">&nbsp;</A>
<H2>NAME</H2>
sd_bus_message_get_signature, sd_bus_message_is_empty, sd_bus_message_has_signature - Query bus message signature
<A NAME="lbAC">&nbsp;</A>
<H2>SYNOPSIS</H2>
<P>
<B>
</B><PRE>
#include &lt;<A HREF="file:///usr/include/systemd/sd-bus.h">systemd/sd-bus.h</A>&gt;
</PRE>
<DL COMPACT>
<DT id="1">
<B>const char* sd_bus_message_get_signature(sd_bus_message&nbsp;*</B><I>message</I><B>, int&nbsp;</B><I>complete</I><B>);</B>
<DT id="2">
<B>int sd_bus_message_is_empty(sd_bus_message&nbsp;*</B><I>message</I><B>);</B>
<DT id="3">
<B>int sd_bus_message_has_signature(sd_bus_message&nbsp;*</B><I>message</I><B>, const&nbsp;char&nbsp;*</B><I>signature</I><B>);</B>
</DL>
<A NAME="lbAD">&nbsp;</A>
<H2>DESCRIPTION</H2>
<P>
<B>sd_bus_message_get_signature()</B>
<DD>returns the signature of message
<I>message</I>. If
<I>complete</I>
is true, the signature of the whole message is returned, and just the signature of the currently open container otherwise.
<P>
<B>sd_bus_message_is_empty()</B>
returns true if the message is empty, i.e. when its signature is empty.
<P>
<B>sd_bus_message_has_signature()</B>
returns true if the signature of the message
<I>message</I>
matches given
<I>signature</I>. Parameter
<I>signature</I>
may be
<B>NULL</B>, this is treated the same as an empty string, which is equivalent to calling
<B>sd_bus_message_is_empty()</B>.
<A NAME="lbAE">&nbsp;</A>
<H2>RETURN VALUE</H2>
<P>
On success,
<B>sd_bus_message_get_signature()</B>
returns the signature, and
<B>NULL</B>
on error.
<P>
The other functions return 0 or a positive integer on success. On failure, they return a negative errno-style error code.
<A NAME="lbAF">&nbsp;</A>
<H3>Errors</H3>
<P>
Returned errors may indicate the following problems:
<P>
<B>-EINVAL</B>
<DL COMPACT><DT id="4"><DD>
The
<I>message</I>
parameter is
<B>NULL</B>.
</DL>
<P>
<B>NULL</B>
<DL COMPACT><DT id="5"><DD>
The
<I>message</I>
parameter is
<B>NULL</B>.
</DL>
<A NAME="lbAG">&nbsp;</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>&nbsp;<B><A HREF="/cgi-bin/man/man2html?1+pkg-config">pkg-config</A></B>(1)
file.
<A NAME="lbAH">&nbsp;</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_message_new">sd_bus_message_new</A></B>(3)
<P>
<HR>
<A NAME="index">&nbsp;</A><H2>Index</H2>
<DL>
<DT id="6"><A HREF="#lbAB">NAME</A><DD>
<DT id="7"><A HREF="#lbAC">SYNOPSIS</A><DD>
<DT id="8"><A HREF="#lbAD">DESCRIPTION</A><DD>
<DT id="9"><A HREF="#lbAE">RETURN VALUE</A><DD>
<DL>
<DT id="10"><A HREF="#lbAF">Errors</A><DD>
</DL>
<DT id="11"><A HREF="#lbAG">NOTES</A><DD>
<DT id="12"><A HREF="#lbAH">SEE ALSO</A><DD>
</DL>
<HR>
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