man: add "internal" to "reference counter"

man/sd_bus_message_new.xml

@@ -99,14 +99,13 @@
     <citerefentry><refentrytitle>sd_bus_message_set_allow_interactive_authorization</refentrytitle><manvolnum>3</manvolnum></citerefentry>.
     </para>
 
-    <para><function>sd_bus_message_ref()</function> increases the reference counter of
+    <para><function>sd_bus_message_ref()</function> increases the internal reference counter of
     <parameter>m</parameter> by one.</para>
 
-    <para><function>sd_bus_message_unref()</function> decreases the reference counter of
+    <para><function>sd_bus_message_unref()</function> decreases the internal reference counter of
     <parameter>m</parameter> by one. Once the reference count has dropped to zero, message object is
-    destroyed and cannot be used anymore, so further calls to
+    destroyed and cannot be used anymore, so further calls to <function>sd_bus_message_ref()</function> or
-    <function>sd_bus_message_ref()</function> or <function>sd_bus_message_unref()</function> are
+    <function>sd_bus_message_unref()</function> are illegal.</para>
-    illegal.</para>
 
     <para><function>sd_bus_message_unrefp()</function> is similar to
     <function>sd_bus_message_unref()</function> but takes a pointer to a

man/sd_bus_slot_ref.xml

@@ -46,10 +46,10 @@
   <refsect1>
     <title>Description</title>
 
-    <para><function>sd_bus_slot_ref()</function> increases the reference counter of
+    <para><function>sd_bus_slot_ref()</function> increases the internal reference counter of
     <parameter>slot</parameter> by one.</para>
 
-    <para><function>sd_bus_slot_unref()</function> decreases the reference counter of
+    <para><function>sd_bus_slot_unref()</function> decreases the internal reference counter of
     <parameter>slot</parameter> by one. Once the reference count has dropped to zero, slot object is
     destroyed and cannot be used anymore, so further calls to <function>sd_bus_slot_ref()</function>
     or <function>sd_bus_slot_unref()</function> are illegal.</para>

man/sd_device_ref.xml

@@ -42,10 +42,10 @@
       </funcprototype>
     </funcsynopsis>
 
-    <para><function>sd_device_ref()</function> increases the reference counter of
+    <para><function>sd_device_ref()</function> increases the internal reference counter of
     <parameter>device</parameter> by one.</para>
 
-    <para><function>sd_device_unref()</function> decreases the reference counter of
+    <para><function>sd_device_unref()</function> decreases the internal reference counter of
     <parameter>device</parameter> by one. Once the reference count has dropped to zero,
     <parameter>device</parameter> is destroyed and cannot be used anymore, so further calls to
     <function>sd_device_ref()</function> or <function>sd_device_unref()</function> are illegal.</para>

man/sd_event_source_unref.xml

@@ -59,16 +59,13 @@
   <refsect1>
     <title>Description</title>
 
-    <para><function>sd_event_source_unref()</function> may be used to
+    <para><function>sd_event_source_unref()</function> may be used to decrement by one the internal reference
-    decrement by one the reference counter of the event source object
+    counter of the event source object specified as <parameter>source</parameter>. The reference counter is
-    specified as <parameter>source</parameter>. The reference counter
+    initially set to one, when the event source is created with calls such as
-    is initially set to one, when the event source is created with calls
+    <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry> or
-    such as
-    <citerefentry><refentrytitle>sd_event_add_io</refentrytitle><manvolnum>3</manvolnum></citerefentry>
-    or
     <citerefentry><refentrytitle>sd_event_add_time</refentrytitle><manvolnum>3</manvolnum></citerefentry>. When
-    the reference counter reaches zero it is removed from its event loop
+    the reference counter reaches zero, the object is detached from the event loop object and destroyed.
-    object and destroyed.</para>
+    </para>
 
     <para><function>sd_event_source_unrefp()</function> is similar to
     <function>sd_event_source_unref()</function> but takes a pointer to a
@@ -78,9 +75,8 @@
     Variable Attribute</ulink>. Note that this function is defined as
     inline function.</para>
 
-    <para><function>sd_event_source_ref()</function> may be used
+    <para><function>sd_event_source_ref()</function> may be used to increase by one the internal reference
-    to increase by one the reference counter of the event source object
+    counter of the event source object specified as <parameter>source</parameter>.</para>
-    specified as <parameter>source</parameter>.</para>
 
     <para><function>sd_event_source_unref()</function>,
     <function>sd_bus_creds_unrefp()</function> and