man: document sd_bus_read(), add more about sd_bus_read_basic()

1 files changed, 152 insertions, 10 deletions

diff --git a/man/sd_bus_message_read_basic.xml b/man/sd_bus_message_read_basic.xml
index c0e04667ca..fb687b5edd 100644
--- a/man/sd_bus_message_read_basic.xml
+++ b/man/sd_bus_message_read_basic.xml
@@ -52,18 +52,130 @@
     </para>
 
     <para>
-      If <parameter>p</parameter> is not NULL, it should contain a pointer to an
-      appropriate object. For example, if <parameter>type</parameter> is
-      <constant>'y'</constant>, the object passed in <parameter>p</parameter>
-      should have type <code>uint8_t *</code>. If <parameter>type</parameter>
-      is <constant>'s'</constant>, the object passed in <parameter>p</parameter>
-      should have type <code>const char **</code>. Note that, if the basic type
-      is a pointer (e.g., <code>const char *</code> in the case of a string),
-      the pointer is only borrowed and the contents must be copied if they are
-      to be used after the end of the messages lifetime. Similarly, during the
-      lifetime of such a pointer, the message must not be modified.
+      If <parameter>p</parameter> is not <constant>NULL</constant>, it should contain
+      a pointer to an appropriate object. For example, if <parameter>type</parameter>
+      is <constant>'y'</constant>, the object passed in <parameter>p</parameter>
+      should have type <code>uint8_t *</code>. If <parameter>type</parameter> is
+      <constant>'s'</constant>, the object passed in <parameter>p</parameter> should
+      have type <code>const char **</code>. Note that, if the basic type is a pointer
+      (e.g., <code>const char *</code> in the case of a string), the pointer is only
+      borrowed and the contents must be copied if they are to be used after the end
+      of the messages lifetime. Similarly, during the lifetime of such a pointer, the
+      message must not be modified. See the table below for a complete list of allowed
+      types.
     </para>
 
+    <table id='format-specifiers'>
+      <title>Item type specifiers</title>
+
+      <tgroup cols='4'>
+        <colspec colname='specifier' />
+        <colspec colname='constant' />
+        <colspec colname='description' />
+        <colspec colname='ctype' />
+        <thead>
+          <row>
+            <entry>Specifier</entry>
+            <entry>Constant</entry>
+            <entry>Description</entry>
+            <entry>Expected C Type</entry>
+          </row>
+        </thead>
+        <tbody>
+          <row>
+            <entry><literal>y</literal></entry>
+            <entry><constant>SD_BUS_TYPE_BYTE</constant></entry>
+            <entry>unsigned integer</entry>
+            <entry>uint8_t *</entry>
+          </row>
+
+          <row>
+            <entry><literal>b</literal></entry>
+            <entry><constant>SD_BUS_TYPE_BOOLEAN</constant></entry>
+            <entry>boolean</entry>
+            <entry>int *</entry>
+          </row>
+
+          <row>
+            <entry><literal>n</literal></entry>
+            <entry><constant>SD_BUS_TYPE_INT16</constant></entry>
+            <entry>signed integer</entry>
+            <entry>int16_t *</entry>
+          </row>
+
+          <row>
+            <entry><literal>q</literal></entry>
+            <entry><constant>SD_BUS_TYPE_UINT16</constant></entry>
+            <entry>unsigned integer</entry>
+            <entry>uint16_t *</entry>
+          </row>
+
+          <row>
+            <entry><literal>i</literal></entry>
+            <entry><constant>SD_BUS_TYPE_INT32</constant></entry>
+            <entry>signed integer</entry>
+            <entry>int32_t *</entry>
+          </row>
+
+          <row>
+            <entry><literal>u</literal></entry>
+            <entry><constant>SD_BUS_TYPE_UINT32</constant></entry>
+            <entry>unsigned integer</entry>
+            <entry>uint32_t *</entry>
+          </row>
+
+          <row>
+            <entry><literal>x</literal></entry>
+            <entry><constant>SD_BUS_TYPE_INT64</constant></entry>
+            <entry>signed integer</entry>
+            <entry>int64_t *</entry>
+          </row>
+
+          <row>
+            <entry><literal>t</literal></entry>
+            <entry><constant>SD_BUS_TYPE_UINT64</constant></entry>
+            <entry>unsigned integer</entry>
+            <entry>uint64_t *</entry>
+          </row>
+
+          <row>
+            <entry><literal>d</literal></entry>
+            <entry><constant>SD_BUS_TYPE_DOUBLE</constant></entry>
+            <entry>floating-point</entry>
+            <entry>double *</entry>
+          </row>
+
+          <row>
+            <entry><literal>s</literal></entry>
+            <entry><constant>SD_BUS_TYPE_STRING</constant></entry>
+            <entry>Unicode string</entry>
+            <entry>const char **</entry>
+          </row>
+
+          <row>
+            <entry><literal>o</literal></entry>
+            <entry><constant>SD_BUS_TYPE_OBJECT_PATH</constant></entry>
+            <entry>object path</entry>
+            <entry>const char **</entry>
+          </row>
+
+          <row>
+            <entry><literal>g</literal></entry>
+            <entry><constant>SD_BUS_TYPE_SIGNATURE</constant></entry>
+            <entry>signature</entry>
+            <entry>const char **</entry>
+          </row>
+
+          <row>
+            <entry><literal>h</literal></entry>
+            <entry><constant>SD_BUS_TYPE_UNIX_FD</constant></entry>
+            <entry>UNIX file descriptor</entry>
+            <entry>int *</entry>
+          </row>
+       </tbody>
+      </tgroup>
+    </table>
+
     <para>
       If there is no object of the specified type at the current position in the
       message, an error is returned.
@@ -80,12 +192,42 @@
     </para>
   </refsect1>
 
+  <refsect1 id='errors'>
+    <title>Errors</title>
+
+    <para>Returned errors may indicate the following problems:</para>
+
+    <variablelist>
+      <varlistentry>
+        <term><constant>-EINVAL</constant></term>
+
+        <listitem><para>Specified type string is invalid or the message parameter is
+        <constant>NULL</constant>.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><constant>-ENXIO</constant></term>
+
+        <listitem><para>The message does not contain the specified type at current
+        position.</para></listitem>
+      </varlistentry>
+
+      <varlistentry>
+        <term><constant>-EBADMSG</constant></term>
+
+        <listitem><para>The message cannot be parsed.</para></listitem>
+      </varlistentry>
+    </variablelist>
+  </refsect1>
+
   <refsect1>
     <title>See Also</title>
 
     <para>
       <citerefentry><refentrytitle>systemd</refentrytitle><manvolnum>1</manvolnum></citerefentry>,
       <citerefentry><refentrytitle>sd-bus</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_message_append_basic</refentrytitle><manvolnum>3</manvolnum></citerefentry>,
+      <citerefentry><refentrytitle>sd_bus_message_read</refentrytitle><manvolnum>3</manvolnum></citerefentry>
     </para>
   </refsect1>