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1 | <?xml version='1.0'?> |
2 | <!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.2//EN" | |
3 | "http://www.oasis-open.org/docbook/xml/4.2/docbookx.dtd"> | |
4 | ||
5 | <!-- | |
6 | SPDX-License-Identifier: LGPL-2.1+ | |
7 | --> | |
8 | ||
9 | <refentry id="sd_bus_message_new_method_error" | |
10 | xmlns:xi="http://www.w3.org/2001/XInclude"> | |
11 | ||
12 | <refentryinfo> | |
13 | <title>sd_bus_message_new_method_error</title> | |
14 | <productname>systemd</productname> | |
15 | </refentryinfo> | |
16 | ||
17 | <refmeta> | |
18 | <refentrytitle>sd_bus_message_new_method_error</refentrytitle> | |
19 | <manvolnum>3</manvolnum> | |
20 | </refmeta> | |
21 | ||
22 | <refnamediv> | |
23 | <refname>sd_bus_message_new_method_error</refname> | |
24 | <refname>sd_bus_message_new_method_errorf</refname> | |
25 | <refname>sd_bus_message_new_method_errno</refname> | |
26 | <refname>sd_bus_message_new_method_errnof</refname> | |
27 | ||
28 | <refpurpose>Create a an error reply for a method call</refpurpose> | |
29 | </refnamediv> | |
30 | ||
31 | <refsynopsisdiv> | |
32 | <funcsynopsis> | |
33 | <funcsynopsisinfo>#include <systemd/sd-bus.h></funcsynopsisinfo> | |
34 | ||
35 | <funcprototype> | |
36 | <funcdef>int sd_bus_message_new_method_error</funcdef> | |
37 | <paramdef>sd_bus_message *<parameter>call</parameter></paramdef> | |
38 | <paramdef>sd_bus_message **<parameter>m</parameter></paramdef> | |
39 | <paramdef>const sd_bus_error *<parameter>e</parameter></paramdef> | |
40 | </funcprototype> | |
41 | ||
42 | <funcprototype> | |
43 | <funcdef>int sd_bus_message_new_method_errorf</funcdef> | |
44 | <paramdef>sd_bus_message *<parameter>call</parameter></paramdef> | |
45 | <paramdef>sd_bus_message **<parameter>m</parameter></paramdef> | |
46 | <paramdef>const char *<parameter>name</parameter></paramdef> | |
47 | <paramdef>const char *<parameter>format</parameter></paramdef> | |
48 | <paramdef>…</paramdef> | |
49 | </funcprototype> | |
50 | ||
51 | <funcprototype> | |
52 | <funcdef>int sd_bus_message_new_method_errno</funcdef> | |
53 | <paramdef>sd_bus_message *<parameter>call</parameter></paramdef> | |
54 | <paramdef>sd_bus_message **<parameter>m</parameter></paramdef> | |
55 | <paramdef>int <parameter>error</parameter></paramdef> | |
56 | <paramdef>const sd_bus_error *<parameter>p</parameter></paramdef> | |
57 | </funcprototype> | |
58 | ||
59 | <funcprototype> | |
60 | <funcdef>int sd_bus_message_new_method_errnof</funcdef> | |
61 | <paramdef>sd_bus_message *<parameter>call</parameter></paramdef> | |
62 | <paramdef>sd_bus_message **<parameter>m</parameter></paramdef> | |
63 | <paramdef>int <parameter>error</parameter></paramdef> | |
64 | <paramdef>const char *<parameter>format</parameter></paramdef> | |
65 | <paramdef>…</paramdef> | |
66 | </funcprototype> | |
67 | </funcsynopsis> | |
68 | </refsynopsisdiv> | |
69 | ||
70 | <refsect1> | |
71 | <title>Description</title> | |
72 | ||
73 | <para>The <function>sd_bus_message_new_method_error()</function> function creates | |
74 | a new bus message object that is an error reply to the | |
75 | <parameter>call</parameter> message, and returns it in the | |
76 | <parameter>m</parameter> output parameter. The error information from error | |
77 | <parameter>e</parameter> is appended: the <parameter>name</parameter> field of | |
78 | <parameter>e</parameter> is used as the error identifier in the reply header (for | |
79 | example an error name such as | |
80 | <literal>org.freedesktop.DBus.Error.NotSupported</literal> or the equivalent | |
81 | symbolic <constant>SD_BUS_ERROR_NOT_SUPPORTED</constant>), and the | |
82 | <parameter>message</parameter> field is set as the human readable error message | |
83 | string if present. The error <parameter>e</parameter> must have the | |
84 | <parameter>name</parameter> field set, see | |
85 | <citerefentry><refentrytitle>sd_bus_error_is_set</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
86 | </para> | |
87 | ||
88 | <para>The <function>sd_bus_message_new_method_errorf()</function> function | |
89 | creates an error reply similarly to | |
90 | <function>sd_bus_message_new_method_error()</function>, but instead of a ready | |
91 | error structure, it takes an error identifier string <parameter>name</parameter>, | |
92 | plus a <citerefentry | |
93 | project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
94 | format string <parameter>format</parameter> and corresponding arguments. An error | |
95 | reply is sent with the error identifier <parameter>name</parameter> and the | |
96 | formatted string as the message. <parameter>name</parameter> and | |
97 | <parameter>format</parameter> must not be <constant>NULL</constant>. | |
98 | </para> | |
99 | ||
100 | <para>The <function>sd_bus_message_new_method_errno()</function> function creates | |
101 | an error reply similarly to | |
102 | <function>sd_bus_message_new_method_error()</function>, but in addition to the | |
103 | error structure <parameter>p</parameter>, it takes an | |
104 | <citerefentry><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
105 | error value in parameter <parameter>error</parameter>. If the error | |
106 | <parameter>p</parameter> is set (see | |
107 | <citerefentry><refentrytitle>sd_bus_error_is_set</refentrytitle><manvolnum>3</manvolnum></citerefentry>), | |
108 | it is used in the reply. Otherwise, <parameter>error</parameter> is translated to | |
109 | an error identifier and used to create a new error structure using | |
110 | <citerefentry><refentrytitle>sd_bus_error_set_errno</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
111 | and that is used in the reply. (If <parameter>error</parameter> is zero, no error | |
112 | is actually set, and an error reply with no information is created.)</para> | |
113 | ||
114 | <para>The <function>sd_bus_message_new_method_errnof()</function> function | |
115 | creates an error reply similarly to | |
116 | <function>sd_bus_message_new_method_error()</function>. It takes an | |
117 | <citerefentry><refentrytitle>errno</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
118 | error value in parameter <parameter>error</parameter>, plus a <citerefentry | |
119 | project='man-pages'><refentrytitle>printf</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
120 | format string <parameter>format</parameter> and corresponding arguments. | |
121 | <literal>%m</literal> may be used in the format string to refer to the error | |
122 | string corresponding to the specified errno code. The error message is initalized | |
123 | using the error identifier generated from <constant>error</constant> and the | |
124 | formatted string. (If <parameter>error</parameter> is zero, no error is actually | |
125 | set, and an error reply with no information is created.)</para> | |
126 | </refsect1> | |
127 | ||
128 | <refsect1> | |
129 | <title>Return Value</title> | |
130 | ||
131 | <para>These functions return 0 if the error reply was successfully created, and a | |
132 | negative errno-style error code otherwise.</para> | |
133 | </refsect1> | |
134 | ||
135 | <refsect1 id='errors'> | |
136 | <title>Errors</title> | |
137 | ||
138 | <para>Returned errors may indicate the following problems:</para> | |
139 | ||
140 | <variablelist> | |
141 | <varlistentry> | |
142 | <term><constant>-EINVAL</constant></term> | |
143 | ||
144 | <listitem><para>The call message <parameter>call</parameter> or the output | |
145 | parameter <parameter>m</parameter> are <constant>NULL</constant>.</para> | |
146 | ||
147 | <para>Message <parameter>call</parameter> is not a method call | |
148 | message.</para> | |
149 | ||
150 | <para>The error <parameter>error</parameter> parameter to | |
151 | <function>sd_bus_message_new_method_error</function> is not set, see | |
152 | <citerefentry><refentrytitle>sd_bus_error_is_set</refentrytitle><manvolnum>3</manvolnum></citerefentry>. | |
153 | </para> | |
154 | </listitem> | |
155 | </varlistentry> | |
156 | ||
157 | <varlistentry> | |
158 | <term><constant>-EPERM</constant></term> | |
159 | ||
160 | <listitem><para>Message <parameter>call</parameter> has been sealed. | |
161 | </para></listitem> | |
162 | </varlistentry> | |
163 | ||
164 | <varlistentry> | |
165 | <term><constant>-ENOTCONN</constant></term> | |
166 | ||
167 | <listitem><para>The bus to which message <parameter>call</parameter> is | |
168 | attached is not connected.</para></listitem> | |
169 | </varlistentry> | |
170 | ||
171 | <varlistentry> | |
172 | <term><constant>-ENOMEM</constant></term> | |
173 | ||
174 | <listitem><para>Memory allocation failed.</para></listitem> | |
175 | </varlistentry> | |
176 | </variablelist> | |
177 | </refsect1> | |
178 | ||
179 | <xi:include href="libsystemd-pkgconfig.xml" /> | |
180 | ||
181 | <refsect1> | |
182 | <title>See Also</title> | |
183 | ||
184 | <para> | |
185 | <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>, | |
186 | <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry> | |
187 | </para> | |
188 | </refsect1> | |
189 | ||
190 | </refentry> |