sd_bus_message_get_cookie.html 6.02 KB
Newer Older
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21
<html><head><meta http-equiv="Content-Type" content="text/html; charset=UTF-8"><title>sd_bus_message_get_cookie</title><meta name="generator" content="DocBook XSL Stylesheets V1.78.1"></head><body bgcolor="white" text="black" link="#0000FF" vlink="#840084" alink="#0000FF"><style>
    a.headerlink {
      color: #c60f0f;
      font-size: 0.8em;
      padding: 0 4px 0 4px;
      text-decoration: none;
      visibility: hidden;
    }

    a.headerlink:hover {
      background-color: #c60f0f;
      color: white;
    }

    h1:hover > a.headerlink, h2:hover > a.headerlink, h3:hover > a.headerlink, dt:hover > a.headerlink {
      visibility: visible;
    }
  </style><a href="index.html">Index </a>·
  <a href="systemd.directives.html">Directives </a>·
  <a href="../python-systemd/index.html">Python </a>·
  <a href="../libudev/index.html">libudev </a>·
Michael Biebl's avatar
Michael Biebl committed
22
  <a href="../libudev/index.html">gudev </a><span style="float:right">systemd 215</span><hr><div class="refentry"><a name="sd_bus_message_get_cookie"></a><div class="titlepage"></div><div class="refnamediv"><h2>Name</h2><p>sd_bus_message_get_cookie, sd_bus_message_get_reply_cookie — Returns the transaction cookie of a message</p></div><div class="refsynopsisdiv"><h2>Synopsis</h2><div class="funcsynopsis"><pre class="funcsynopsisinfo">#include &lt;systemd/sd-bus.h&gt;</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_bus_message_get_cookie</b>(</code></td><td>sd_bus_message *<var class="pdparam">message</var>, </td></tr><tr><td> </td><td>uint64_t *<var class="pdparam">cookie</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_bus_message_get_reply_cookie</b>(</code></td><td>sd_bus_message *<var class="pdparam">message</var>, </td></tr><tr><td> </td><td>uint64_t *<var class="pdparam">cookie</var><code>)</code>;</td></tr></table><div class="funcprototype-spacer"> </div></div></div><div class="refsect1"><a name="idm214165938928"></a><h2 id="Description">Description<a class="headerlink" title="Permalink to this headline" href="#Description"></a></h2><p><code class="function">sd_bus_message_get_cookie()</code> returns
23 24 25 26 27 28 29 30 31 32 33 34
                the transaction cookie of a message. The cookie
                uniquely identifies a message within each bus peer,
                but is not globally unique. It is assigned when a
                message is sent.</p><p><code class="function">sd_bus_message_get_reply_cookie()</code>
                returns the transaction cookie of the message the
                specified message is a response to. When a reply
                message is generated for a method call message, its
                cookie is copied over into this field. Note that while
                every message that is transferred is identified by a
                cookie, only response messages carry a reply cookie
                field.</p><p>Both functions take a message object as first
                parameter and a place to store the 64-bit cookie
Michael Biebl's avatar
Michael Biebl committed
35
                in.</p></div><div class="refsect1"><a name="idm214168449712"></a><h2 id="Return Value">Return Value<a class="headerlink" title="Permalink to this headline" href="#Return%20Value"></a></h2><p>On success, these calls return 0 or a positive
36 37
                integer. On failure, these calls return a negative
                errno-style error code.</p><p>On success, the cookie/reply cookie is returned
Michael Biebl's avatar
Michael Biebl committed
38
                in the specified 64-bit unsigned integer variable.</p></div><div class="refsect1"><a name="idm214167487344"></a><h2 id="Errors">Errors<a class="headerlink" title="Permalink to this headline" href="#Errors"></a></h2><p>Returned errors may indicate the following problems:</p><div class="variablelist"><dl class="variablelist"><dt id="-EINVAL"><span class="term"><code class="varname">-EINVAL</code></span><a class="headerlink" title="Permalink to this term" href="#-EINVAL"></a></dt><dd><p>A specified parameter
39 40 41 42 43 44 45
                                is invalid.</p></dd><dt id="-ENODATA"><span class="term"><code class="varname">-ENODATA</code></span><a class="headerlink" title="Permalink to this term" href="#-ENODATA"></a></dt><dd><p>No cookie has been
                                assigned to this message. This either
                                indicates that the message has not
                                been sent yet and hence has no cookie
                                assigned, or that the message is not a
                                method response message and hence
                                carries a reply cookie
Michael Biebl's avatar
Michael Biebl committed
46
                                field.</p></dd></dl></div></div><div class="refsect1"><a name="idm214166489008"></a><h2 id="Notes">Notes<a class="headerlink" title="Permalink to this headline" href="#Notes"></a></h2><p>The <code class="function">sd_bus_message_get_cookie()</code>
47 48 49 50
                and <code class="function">sd_bus_message_get_reply_cookie()</code>
                interfaces are available as a shared library, which can
                be compiled and linked to with the
                <code class="constant">libsystemd</code> <a href="pkg-config.html"><span class="citerefentry"><span class="refentrytitle">pkg-config</span>(1)</span></a>
Michael Biebl's avatar
Michael Biebl committed
51
                file.</p></div><div class="refsect1"><a name="idm214166665392"></a><h2 id="See Also">See Also<a class="headerlink" title="Permalink to this headline" href="#See%20Also"></a></h2><p>
52 53 54 55
                        <a href="systemd.html"><span class="citerefentry"><span class="refentrytitle">systemd</span>(1)</span></a>,
                        <a href="sd-bus.html"><span class="citerefentry"><span class="refentrytitle">sd-bus</span>(3)</span></a>,
                        <a href="sd_bus_new.html"><span class="citerefentry"><span class="refentrytitle">sd_bus_new</span>(3)</span></a>
                </p></div></div></body></html>