Update Kernel documentation

Language cleaned up by technical writers from Combitech.
Proofreading and corrections by Björn Gustavsson and
Hans Bolinder.

1 files changed, 238 insertions, 219 deletions

diff --git a/lib/kernel/doc/src/application.xml b/lib/kernel/doc/src/application.xml
index 4d8e6ce94b..16de17c901 100644
--- a/lib/kernel/doc/src/application.xml
+++ b/lib/kernel/doc/src/application.xml
@@ -33,23 +33,25 @@
   <description>
     <p>In OTP, <em>application</em> denotes a component implementing
       some specific functionality, that can be started and stopped as a
-      unit, and which can be re-used in other systems as well. This
-      module interfaces the <em>application controller</em>, a process
-      started at every Erlang runtime system, and contains functions
-      for controlling applications (for example starting and stopping
+      unit, and that can be reused in other systems. This
+      module interacts with <em>application controller</em>, a process
+      started at every Erlang runtime system. This module contains functions
+      for controlling applications (for example, starting and stopping
       applications), and functions to access information about
-      applications (for example configuration parameters).</p>
-    <p>An application is defined by an <em>application specification</em>. The specification is normally located in an
-      <em>application resource file</em> called <c>Application.app</c>,
-      where <c>Application</c> is the name of the application. Refer to
-      <seealso marker="app">app(4)</seealso> for more information about
-      the application specification.</p>
+      applications (for example, configuration parameters).</p>
+    <p>An application is defined by an <em>application specification</em>.
+      The specification is normally located in an
+      <em>application resource file</em> named <c>Application.app</c>,
+      where <c>Application</c> is the application name. For details
+      about the application specification, see
+    <seealso marker="app"><c>app(4)</c></seealso>.</p>
     <p>This module can also be viewed as a behaviour for an application
       implemented according to the OTP design principles as a
       supervision tree. The definition of how to start and stop
-      the tree should be located in an <em>application callback module</em> exporting a pre-defined set of functions.</p>
-    <p>Refer to <seealso marker="doc/design_principles:des_princ">OTP Design Principles</seealso> for more information about
-      applications and behaviours.</p>
+      the tree is to be located in an <em>application callback module</em>,
+      exporting a predefined set of functions.</p>
+    <p>For details about applications and behaviours, see
+    <seealso marker="doc/design_principles:des_princ">OTP Design Principles</seealso>.</p>
   </description>
   <datatypes>
     <datatype>
@@ -59,7 +61,6 @@
       <name name="restart_type"/>
     </datatype>
     <datatype>
-      <!-- Parameterized opaque types are NYI: -->
       <name>tuple_of(T)</name>
       <desc><p><marker id="type-tuple_of"/>
         A tuple where the elements are of type <c>T</c>.</p></desc>
@@ -67,9 +68,37 @@
   </datatypes>
   <funcs>
     <func>
+        <name name="ensure_all_started" arity="1"/>
+        <name name="ensure_all_started" arity="2"/>
+        <fsummary>Load and start an application and its dependencies, recursively.</fsummary>
+        <desc>
+          <p>Equivalent to calling
+	  <seealso marker="#start/1"><c>start/1,2</c></seealso>
+          repeatedly on all dependencies that are not yet started for an application.</p>
+          <p>Returns <c>{ok, AppNames}</c> for a successful start or for an already started
+          application (which is, however, omitted from the <c>AppNames</c> list).</p>
+	  <p>The function reports <c>{error, {AppName,Reason}}</c> for errors, where
+	  <c>Reason</c> is any possible reason returned by
+	  <seealso marker="#start/1"><c>start/1,2</c></seealso>
+	  when starting a specific dependency.</p>
+	  <p>If an error occurs, the applications started by the function are stopped
+	  to bring the set of running applications back to its initial state.</p>
+        </desc>
+    </func>
+    <func>
+      <name name="ensure_started" arity="1"/>
+      <name name="ensure_started" arity="2"/>
+      <fsummary>Load and start an application.</fsummary>
+      <desc>
+	<p>Equivalent to
+	<seealso marker="#start/1"><c>start/1,2</c></seealso>
+	except it returns <c>ok</c> for already started applications.</p>
+      </desc>
+    </func>
+    <func>
       <name name="get_all_env" arity="0"/>
       <name name="get_all_env" arity="1"/>
-      <fsummary>Get the configuration parameters for an application</fsummary>
+      <fsummary>Get the configuration parameters for an application.</fsummary>
       <desc>
         <p>Returns the configuration parameters and their values for
           <c><anno>Application</anno></c>. If the argument is omitted, it defaults to
@@ -82,7 +111,7 @@
     <func>
       <name name="get_all_key" arity="0"/>
       <name name="get_all_key" arity="1"/>
-      <fsummary>Get the application specification keys</fsummary>
+      <fsummary>Get the application specification keys.</fsummary>
       <desc>
         <p>Returns the application specification keys and their values
           for <c><anno>Application</anno></c>. If the argument is omitted, it
@@ -96,7 +125,7 @@
     <func>
       <name name="get_application" arity="0"/>
       <name name="get_application" arity="1"/>
-      <fsummary>Get the name of an application containing a certain process or module</fsummary>
+      <fsummary>Get the name of an application containing a certain process or module.</fsummary>
       <desc>
         <p>Returns the name of the application to which the process
           <c><anno>Pid</anno></c> or the module <c><anno>Module</anno></c> belongs. Providing no
@@ -110,222 +139,212 @@
     <func>
       <name name="get_env" arity="1"/>
       <name name="get_env" arity="2"/>
-      <fsummary>Get the value of a configuration parameter</fsummary>
+      <fsummary>Get the value of a configuration parameter.</fsummary>
       <desc>
-        <p>Returns the value of the configuration parameter <c><anno>Par</anno></c>
+        <p>Returns the value of configuration parameter <c><anno>Par</anno></c>
           for <c><anno>Application</anno></c>. If the application argument is
           omitted, it defaults to the application of the calling
           process.</p>
-        <p>If the specified application is not loaded, or
-          the configuration parameter does not exist, or if the process
-          executing the call does not belong to any application,
-          the function returns <c>undefined</c>.</p>
+	  <p>Returns <c>undefined</c> if any of the following applies:</p>
+	  <list type="bulleted">
+	    <item>The specified application is not loaded.</item>
+	    <item>The configuration parameter does not exist.</item>
+	    <item>The process executing the call does not belong to any application.</item>
+	  </list>
       </desc>
     </func>
     <func>
       <name name="get_env" arity="3"/>
-      <fsummary>Get the value of a configuration parameter using a default</fsummary>
+      <fsummary>Get the value of a configuration parameter using a default.</fsummary>
       <desc>
-        <p>Works like <seealso marker="#get_env/2">get_env/2</seealso> but returns
-          <c><anno>Def</anno></c> value when configuration parameter
+        <p>Works like <seealso marker="#get_env/2"><c>get_env/2</c></seealso> but returns
+          value <c><anno>Def</anno></c> when configuration parameter
           <c><anno>Par</anno></c> does not exist.</p>
       </desc>
     </func>
     <func>
       <name name="get_key" arity="1"/>
       <name name="get_key" arity="2"/>
-      <fsummary>Get the value of an application specification key</fsummary>
+      <fsummary>Get the value of an application specification key.</fsummary>
       <desc>
         <p>Returns the value of the application specification key
           <c><anno>Key</anno></c> for <c><anno>Application</anno></c>. If the application
           argument is omitted, it defaults to the application of
           the calling process.</p>
-        <p>If the specified application is not loaded, or
-          the specification key does not exist, or if the process
-          executing the call does not belong to any application,
-          the function returns <c>undefined</c>.</p>
+	  <p>Returns <c>undefined</c> if any of the following applies:</p>
+	  <list type="bulleted">
+	    <item>The specified application is not loaded.</item>
+	    <item>The specification key does not exist.</item>
+	    <item>The process executing the call does not belong to any application.</item>
+	  </list>
+
       </desc>
     </func>
     <func>
       <name name="load" arity="1"/>
       <name name="load" arity="2"/>
-      <fsummary>Load an application</fsummary>
+      <fsummary>Load an application.</fsummary>
       <type name="application_spec"/>
       <type name="application_opt"/>
       <desc>
         <p>Loads the application specification for an application into
-          the application controller. It will also load the application
-          specifications for any included applications. Note that
-          the function does not load the actual Erlang object code.</p>
-        <p>The application can be given by its name <c><anno>Application</anno></c>.
-          In this case the application controller will search the code
+          the application controller. It also loads the application
+          specifications for any included applications. Notice that
+          the function does not load the Erlang object code.</p>
+        <p>The application can be specified by its name <c><anno>Application</anno></c>.
+          In this case, the application controller searches the code
           path for the application resource file <c><anno>Application</anno>.app</c>
-          and load the specification it contains.</p>
-        <p>The application specification can also be given directly as a
-          tuple <c><anno>AppSpec</anno></c>. This tuple should have the format and
-          contents as described in <c>app(4)</c>.</p>
+          and loads the specification it contains.</p>
+        <p>The application specification can also be specified directly as a
+          tuple <c><anno>AppSpec</anno></c>, having the format and
+          contents as described in
+	<seealso marker="app"><c>app(4)</c></seealso>.</p>
         <p>If <c><anno>Distributed</anno> == {<anno>Application</anno>,[<anno>Time</anno>,]<anno>Nodes</anno>}</c>,
-          the application will be distributed. The argument overrides
-          the value for the application in the Kernel configuration
+          the application becomes distributed. The argument overrides
+          the value for the application in the <c>Kernel</c> configuration
           parameter <c>distributed</c>. <c><anno>Application</anno></c> must be
-          the name of the application (same as in the first argument).
-          If a node crashes and <c><anno>Time</anno></c> has been specified, then
-          the application controller will wait for <c><anno>Time</anno></c>
+          the application name (same as in the first argument).
+          If a node crashes and <c><anno>Time</anno></c> is specified,
+          the application controller waits for <c><anno>Time</anno></c>
           milliseconds before attempting to restart the application on
-          another node. If <c><anno>Time</anno></c> is not specified, it will
-          default to 0 and the application will be restarted
+          another node. If <c><anno>Time</anno></c> is not specified, it
+          defaults to <c>0</c> and the application is restarted
           immediately.</p>
         <p><c><anno>Nodes</anno></c> is a list of node names where the application
-          may run, in priority from left to right. Node names can be
+          can run, in priority from left to right. Node names can be
           grouped using tuples to indicate that they have the same
-          priority. Example:</p>
+          priority.</p>
+	  <p><em>Example:</em></p>
         <code type="none">
 Nodes = [cp1@cave, {cp2@cave, cp3@cave}]</code>
-        <p>This means that the application should preferably be started
+        <p>This means that the application is preferably to be started
           at <c>cp1@cave</c>. If <c>cp1@cave</c> is down,
-          the application should be started at either <c>cp2@cave</c>
+          the application is to be started at <c>cp2@cave</c>
           or <c>cp3@cave</c>.</p>
         <p>If <c>Distributed == default</c>, the value for
-          the application in the Kernel configuration parameter
-          <c>distributed</c> will be used.</p>
+          the application in the <c>Kernel</c> configuration parameter
+          <c>distributed</c> is used.</p>
       </desc>
     </func>
     <func>
       <name name="loaded_applications" arity="0"/>
-      <fsummary>Get the currently loaded applications</fsummary>
+      <fsummary>Get the currently loaded applications.</fsummary>
       <desc>
-        <p>Returns a list with information about the applications which
-          have been loaded using <c>load/1,2</c>, also included
-          applications. <c><anno>Application</anno></c> is the application name.
-          <c><anno>Description</anno></c> and <c><anno>Vsn</anno></c> are the values of its
-          <c>description</c> and <c>vsn</c> application specification
+        <p>Returns a list with information about the applications, and included
+	  applications, which are loaded using <c>load/1,2</c>.
+          <c><anno>Application</anno></c> is the application name.
+          <c><anno>Description</anno></c> and <c><anno>Vsn</anno></c> are the values
+	  of their <c>description</c> and <c>vsn</c> application specification
           keys, respectively.</p>
       </desc>
     </func>
     <func>
       <name name="permit" arity="2"/>
-      <fsummary>Change an application's permission to run on a node.</fsummary>
+      <fsummary>Change the permission for an application to run at a node.</fsummary>
       <desc>
         <p>Changes the permission for <c><anno>Application</anno></c> to run at
-          the current node. The application must have been loaded using
+          the current node. The application must be loaded using
           <c>load/1,2</c> for the function to have effect.</p>
         <p>If the permission of a loaded, but not started, application
-          is set to <c>false</c>, <c>start</c> will return <c>ok</c> but
-          the application will not be started until the permission is
+          is set to <c>false</c>, <c>start</c> returns <c>ok</c> but
+          the application is not started until the permission is
           set to <c>true</c>.</p>
         <p>If the permission of a running application is set to
-          <c>false</c>, the application will be stopped. If
-          the permission later is set to <c>true</c>, it will be
+          <c>false</c>, the application is stopped. If
+          the permission later is set to <c>true</c>, it is
           restarted.</p>
         <p>If the application is distributed, setting the permission to
           <c>false</c> means that the application will be started at, or
           moved to, another node according to how its distribution is
-          configured (see <c>load/2</c> above).</p>
+          configured
+	(see <seealso marker="#load/2"><c>load/2</c></seealso>).</p>
         <p>The function does not return until the application is
-          started, stopped or successfully moved to another node.
-          However, in some cases where permission is set to <c>true</c>
-          the function may return <c>ok</c> even though the application
-          itself has not started. This is true when an application
-          cannot start because it has dependencies to other
-          applications which have not yet been started. When they have
-          been started, <c>Application</c> will be started as well.</p>
+          started, stopped, or successfully moved to another node.
+          However, in some cases where permission is set to <c>true</c>,
+          the function returns <c>ok</c> even though the application
+          is not started. This is true when an application
+          cannot start because of dependencies to other
+          applications that are not yet started. When they are
+          started, <c>Application</c> is started as well.</p>
         <p>By default, all applications are loaded with permission
-          <c>true</c> on all nodes. The permission is configurable by
-          using the Kernel configuration parameter <c>permissions</c>.</p>
+          <c>true</c> on all nodes. The permission can be configured
+          using the <c>Kernel</c> configuration parameter <c>permissions</c>.</p>
       </desc>
     </func>
     <func>
       <name name="set_env" arity="3"/>
       <name name="set_env" arity="4"/>
-      <fsummary>Set the value of a configuration parameter</fsummary>
+      <fsummary>Set the value of a configuration parameter.</fsummary>
       <desc>
-        <p>Sets the value of the configuration parameter <c><anno>Par</anno></c> for
+        <p>Sets the value of configuration parameter <c><anno>Par</anno></c> for
           <c><anno>Application</anno></c>.</p>
-        <p><c>set_env/4</c> uses the standard <c>gen_server</c> timeout
-          value (5000 ms). The <c>timeout</c> option can be provided
-          if another timeout value is useful, for example, in situations
+        <p><c>set_env/4</c> uses the standard <c>gen_server</c> time-out
+          value (5000 ms). Option <c>timeout</c> can be specified
+          if another time-out value is useful, for example, in situations
           where the application controller is heavily loaded.</p>
         <p>If <c>set_env/4</c> is called before the application is loaded,
-          the application environment values specified in the <c>Application.app</c>
-          file will override the ones previously set. This is also true for application
+          the application environment values specified in file <c>Application.app</c>
+          override the ones previously set. This is also true for application
           reloads.</p>
-        <p>The <c>persistent</c> option can be set to <c>true</c>
-          when there is a need to guarantee parameters set with <c>set_env/4</c>
-          will not be overridden by the ones defined in the application resource
-          file on load. This means persistent values will stick after the application
+        <p>Option <c>persistent</c> can be set to <c>true</c>
+          to guarantee that parameters set with <c>set_env/4</c>
+          are not overridden by those defined in the application resource
+          file on load. This means that persistent values will stick after the application
           is loaded and also on application reload.</p>
         <warning>
-          <p>Use this function only if you know what you are doing, 
-            that is, on your own applications. It is very application
-            and configuration parameter dependent when and how often
-            the value is read by the application, and careless use 
-            of this function may put the application in a 
-            weird, inconsistent, and malfunctioning state. </p>
+          <p>Use this function only if you know what you are doing,
+            that is, on your own applications. It is very
+	    application-dependent and
+	    configuration parameter-dependent when and how often
+            the value is read by the application. Careless use
+            of this function can put the application in a
+            weird, inconsistent, and malfunctioning state.</p>
         </warning>
       </desc>
     </func>
     <func>
-      <name name="ensure_started" arity="1"/>
-      <name name="ensure_started" arity="2"/>
-      <fsummary>Load and start an application</fsummary>
-      <desc>
-	<p>Equivalent to <seealso marker="#start/2"><c>application:start/1,2</c></seealso> except
-	it returns <c>ok</c> for already started applications.</p>
-      </desc>
-    </func>
-    <func>
-        <name name="ensure_all_started" arity="1"/>
-        <name name="ensure_all_started" arity="2"/>
-        <fsummary>Load and start an application and its dependencies, recursively</fsummary>
-        <desc>
-            <p>Equivalent to calling <seealso marker="#start/2"><c>application:start/1,2</c></seealso>
-               repeatedly on all dependencies that have not yet been started for an application.
-               The function returns <c>{ok, AppNames}</c> for a successful start or for an already started
-               application (which are however omitted from the <c>AppNames</c> list), and reports
-               <c>{error, {AppName,Reason}}</c> for errors, where <c>Reason</c> is any possible reason
-               returned by <seealso marker="#start/2"><c>application:start/1,2</c></seealso> when starting a
-               specific dependency. In case of an error, the applications that were started by the
-               function are stopped to bring the set of running applications back to its initial state.</p>
-        </desc>
-    </func>
-    <func>
       <name name="start" arity="1"/>
       <name name="start" arity="2"/>
-      <fsummary>Load and start an application</fsummary>
-      <desc>
+      <fsummary>Load and start an application.</fsummary>
+       <desc>
         <p>Starts <c><anno>Application</anno></c>. If it is not loaded,
-          the application controller will first load it using
-          <c>load/1</c>. It will make sure any included applications
-          are loaded, but will not start them. That is assumed to be
+          the application controller first loads it using
+          <c>load/1</c>. It ensures that any included applications
+          are loaded, but does not start them. That is assumed to be
           taken care of in the code for <c><anno>Application</anno></c>.</p>
         <p>The application controller checks the value of
           the application specification key <c>applications</c>, to
-          ensure that all applications that should be started before
-          this application are running. If not,
+          ensure that all applications needed to be started before
+          this application are running. Otherwise,
           <c>{error,{not_started,App}}</c> is returned, where <c>App</c>
           is the name of the missing application.</p>
-        <p>The application controller then creates an <em>application master</em> for the application. The application master is
+        <p>The application controller then creates an <em>application master</em>
+	  for the application. The application master is
           the group leader of all the processes in the application.
           The application master starts the application by calling
           the application callback function <c>Module:start/2</c> as
           defined by the application specification key <c>mod</c>.</p>
-        <p>The <c><anno>Type</anno></c> argument specifies the type of
+        <p>Argument <c><anno>Type</anno></c> specifies the type of
           the application. If omitted, it defaults to <c>temporary</c>.</p>
         <list type="bulleted">
           <item>If a permanent application terminates, all other
            applications and the entire Erlang node are also terminated.</item>
-          <item>If a transient application terminates with <c>Reason == normal</c>, this is reported but no other applications are
-           terminated. If a transient application terminates
-           abnormally, all other applications and the entire Erlang
-           node are also terminated.</item>
+          <item>
+	    <list type="bulleted">
+	      <item>If a transient application terminates with <c>Reason == normal</c>,
+	      this is reported but no other applications are terminated.</item>
+	      <item>If a transient application terminates abnormally, all other
+	      applications and the entire Erlang node are also terminated.</item>
+	    </list>
+	   </item>
           <item>If a temporary application terminates, this is reported
            but no other applications are terminated.</item>
         </list>
-        <p>Note that it is always possible to stop an application
+        <p>Notice that an application can always be stopped
           explicitly by calling <c>stop/1</c>. Regardless of the type of
-          the application, no other applications will be affected.</p>
-        <p>Note also that the transient type is of little practical use,
-          since when a supervision tree terminates, the reason is set to
+          the application, no other applications are affected.</p>
+        <p>Notice also that the transient type is of little practical use,
+          because when a supervision tree terminates, the reason is set to
           <c>shutdown</c>, not <c>normal</c>.</p>
       </desc>
     </func>
@@ -334,13 +353,13 @@ Nodes = [cp1@cave, {cp2@cave, cp3@cave}]</code>
       <fsummary>Get the start type of an ongoing application startup.</fsummary>
       <desc>
         <p>This function is intended to be called by a process belonging
-          to an application, when the application is being started, to
-          determine the start type which is either <c><anno>StartType</anno></c> or
+          to an application, when the application is started, to
+          determine the start type, which is <c><anno>StartType</anno></c> or
           <c>local</c>.</p>
-        <p>See <seealso marker="#start_type"><c>Module:start/2</c></seealso> for a description of
-          <c><anno>StartType</anno></c>.</p>
-        <p><c>local</c> is returned if only parts of the application is
-          being restarted (by a supervisor), or if the function is
+        <p>For a description of <c><anno>StartType</anno></c>, see
+	  <seealso marker="#start_type"><c>Module:start/2</c></seealso>.</p>
+        <p><c>local</c> is returned if only parts of the application are
+          restarted (by a supervisor), or if the function is
           called outside a startup.</p>
         <p>If the process executing the call does not belong to any
           application, the function returns <c>undefined</c>.</p>
@@ -348,103 +367,106 @@ Nodes = [cp1@cave, {cp2@cave, cp3@cave}]</code>
     </func>
     <func>
       <name name="stop" arity="1"/>
-      <fsummary>Stop an application</fsummary>
+      <fsummary>Stop an application.</fsummary>
       <desc>
         <p>Stops <c><anno>Application</anno></c>. The application master calls
           <c>Module:prep_stop/1</c>, if such a function is defined, and
-          then tells the top supervisor of the application to shutdown
-          (see <c>supervisor(3)</c>). This means that the entire
+          then tells the top supervisor of the application to shut down
+          (see <seealso marker="stdlib:supervisor"><c>supervisor(3)</c></seealso>).
+	  This means that the entire
           supervision tree, including included applications, is
           terminated in reversed start order. After the shutdown,
           the application master calls <c>Module:stop/1</c>.
           <c>Module</c> is the callback module as defined by
           the application specification key <c>mod</c>.</p>
-        <p>Last, the application master itself terminates. Note that all
-          processes with the application master as group leader, i.e.
+        <p>Last, the application master terminates. Notice that all
+          processes with the application master as group leader, that is,
           processes spawned from a process belonging to the application,
-          thus are terminated as well.</p>
+          are also terminated.</p>
         <p>When stopped, the application is still loaded.</p>
-        <p>In order to stop a distributed application, <c>stop/1</c>
-          has to be called on all nodes where it can execute (that is,
+        <p>To stop a distributed application, <c>stop/1</c>
+          must be called on all nodes where it can execute (that is,
           on all nodes where it has been started). The call to
           <c>stop/1</c> on the node where the application currently
-          executes will stop its execution. The application will not be
-          moved between nodes due to <c>stop/1</c> being called on
+          executes stops its execution. The application is not
+          moved between nodes, as <c>stop/1</c> is called on
           the node where the application currently executes before
           <c>stop/1</c> is called on the other nodes.</p>
       </desc>
     </func>
     <func>
       <name name="takeover" arity="2"/>
-      <fsummary>Take over a distributed application</fsummary>
+      <fsummary>Take over a distributed application.</fsummary>
       <desc>
-        <p>Performs a takeover of the distributed application
+        <p>Takes over the distributed application
           <c><anno>Application</anno></c>, which executes at another node
           <c>Node</c>. At the current node, the application is
           restarted by calling
           <c>Module:start({takeover,Node},StartArgs)</c>. <c>Module</c>
           and <c>StartArgs</c> are retrieved from the loaded application
           specification. The application at the other node is not
-          stopped until the startup is completed, i.e. when
+          stopped until the startup is completed, that is, when
           <c>Module:start/2</c> and any calls to
           <c>Module:start_phase/3</c> have returned.</p>
-        <p>Thus two instances of the application will run simultaneously
-          during the takeover, which makes it possible to transfer data
-          from the old to the new instance. If this is not acceptable
-          behavior, parts of the old instance may be shut down when
-          the new instance is started. Note that the application may
-          not be stopped entirely however, at least the top supervisor
+        <p>Thus, two instances of the application run simultaneously
+          during the takeover, so that data can be transferred
+          from the old to the new instance. If this is not an acceptable
+          behavior, parts of the old instance can be shut down when
+          the new instance is started. However, the application cannot
+          be stopped entirely, at least the top supervisor
           must remain alive.</p>
-        <p>See <c>start/1,2</c> for a description of <c>Type</c>.</p>
+        <p>For a description of <c>Type</c>, see
+	<seealso marker="#start/1"><c>start/1,2</c></seealso>.</p>
       </desc>
     </func>
     <func>
       <name name="unload" arity="1"/>
-      <fsummary>Unload an application</fsummary>
+      <fsummary>Unload an application.</fsummary>
       <desc>
         <p>Unloads the application specification for <c><anno>Application</anno></c>
-          from the application controller. It will also unload
+          from the application controller. It also unloads
           the application specifications for any included applications.
-          Note that the function does not purge the actual Erlang
+          Notice that the function does not purge the Erlang
           object code.</p>
       </desc>
     </func>
     <func>
       <name name="unset_env" arity="2"/>
       <name name="unset_env" arity="3"/>
-      <fsummary>Unset the value of a configuration parameter</fsummary>
+      <fsummary>Unset the value of a configuration parameter.</fsummary>
       <desc>
         <p>Removes the configuration parameter <c><anno>Par</anno></c> and its value
           for <c><anno>Application</anno></c>.</p>
         <p><c>unset_env/2</c> uses the standard <c>gen_server</c>
-          timeout value (5000 ms). The <c>timeout</c> option can be
-          provided if another timeout value is useful, for example, in
+          time-out value (5000 ms). Option <c>timeout</c> can be
+          specified if another time-out value is useful, for example, in
           situations where the application controller is heavily loaded.</p>
         <p><c>unset_env/3</c> also allows the persistent option to be passed
-          (see <c>set_env/4</c> above).</p>
-        <warning>
-          <p>Use this function only if you know what you are doing, 
-            that is, on your own applications. It is very application
-            and configuration parameter dependent when and how often
-            the value is read by the application, and careless use 
-            of this function may put the application in a 
-            weird, inconsistent, and malfunctioning state. </p>
+          (see <seealso marker="#set_env/4"><c>set_env/4</c></seealso>).</p>
+	<warning>
+          <p>Use this function only if you know what you are doing,
+            that is, on your own applications. It is very
+	    application-dependent and configuration
+	    parameter-dependent when and how often
+            the value is read by the application. Careless use
+            of this function can put the application in a
+            weird, inconsistent, and malfunctioning state.</p>
         </warning>
       </desc>
     </func>
     <func>
       <name name="which_applications" arity="0"/>
       <name name="which_applications" arity="1"/>
-      <fsummary>Get the currently running applications</fsummary>
+      <fsummary>Get the currently running applications.</fsummary>
       <desc>
-        <p>Returns a list with information about the applications which
+        <p>Returns a list with information about the applications that
           are currently running. <c><anno>Application</anno></c> is the application
-          name. <c><anno>Description</anno></c> and <c><anno>Vsn</anno></c> are the values of its
-          <c>description</c> and <c>vsn</c> application specification
+          name. <c><anno>Description</anno></c> and <c><anno>Vsn</anno></c> are the
+	  values of their <c>description</c> and <c>vsn</c> application specification
           keys, respectively.</p>
         <p><c>which_applications/0</c> uses the standard
-          <c>gen_server</c> timeout value (5000 ms). A <c><anno>Timeout</anno></c>
-          argument can be provided if another timeout value is useful,
+          <c>gen_server</c> time-out value (5000 ms). A <c><anno>Timeout</anno></c>
+          argument can be specified if another time-out value is useful,
           for example, in situations where the application controller
           is heavily loaded.</p>
       </desc>
@@ -452,81 +474,81 @@ Nodes = [cp1@cave, {cp2@cave, cp3@cave}]</code>
   </funcs>
 
   <section>
-    <title>CALLBACK MODULE</title>
-    <p>The following functions should be exported from an
+    <title>Callback Module</title>
+    <p>The following functions are to be exported from an
       <c>application</c> callback module.</p>
   </section>
   <funcs>
     <func>
       <name>Module:start(StartType, StartArgs) -> {ok, Pid} | {ok, Pid, State} | {error, Reason}</name>
-      <fsummary>Start an application</fsummary>
+      <fsummary>Start an application.</fsummary>
       <type>
-        <v>StartType = <seealso marker="#type-start_type">start_type()</seealso></v>
+        <v>StartType = <seealso marker="#type-start_type"><c>start_type()</c></seealso></v>
         <v>StartArgs = term()</v>
         <v>Pid = pid()</v>
         <v>State = term()</v>
       </type>
       <desc>
         <p>This function is called whenever an application is started
-          using <c>application:start/1,2</c>, and should start
+          using <c>start/1,2</c>, and is to start
           the processes of the application. If the application is
           structured according to the OTP design principles as a
           supervision tree, this means starting the top supervisor of
           the tree.</p>
         <p><marker id="start_type"/><c>StartType</c> defines the type of start:</p>
         <list type="bulleted">
-          <item><c>normal</c> if it's a normal startup.</item>
+          <item><c>normal</c> if it is a normal startup.</item>
           <item><c>normal</c> also if the application is distributed and
-           started at the current node due to a failover from another
+           started at the current node because of a failover from another
            node, and the application specification key <c>start_phases == undefined</c>.</item>
           <item><c>{takeover,Node}</c> if the application is
-           distributed and started at the current node due to a
+           distributed and started at the current node because of a
            takeover from <c>Node</c>, either because
-          <c>application:takeover/2</c> has been called or because
+          <c>takeover/2</c> has been called or because
            the current node has higher priority than <c>Node</c>.</item>
           <item><c>{failover,Node}</c> if the application is
-           distributed and started at the current node due to a
+           distributed and started at the current node because of a
            failover from <c>Node</c>, and the application
            specification key <c>start_phases /= undefined</c>.</item>
         </list>
         <p><c>StartArgs</c> is the <c>StartArgs</c> argument defined by
           the application specification key <c>mod</c>.</p>
-        <p>The function should return <c>{ok,Pid}</c> or
-          <c>{ok,Pid,State}</c> where <c>Pid</c> is the pid of the top
+        <p>The function is to return <c>{ok,Pid}</c> or
+          <c>{ok,Pid,State}</c>, where <c>Pid</c> is the pid of the top
           supervisor and <c>State</c> is any term. If omitted,
-          <c>State</c> defaults to <c>[]</c>. If later the application
-          is stopped, <c>State</c> is passed to
+          <c>State</c> defaults to <c>[]</c>. If the application
+          is stopped later, <c>State</c> is passed to
           <c>Module:prep_stop/1</c>.</p>
       </desc>
     </func>
     <func>
       <name>Module:start_phase(Phase, StartType, PhaseArgs) -> ok | {error, Reason}</name>
-      <fsummary>Extended start of an application</fsummary>
+      <fsummary>Extended start of an application.</fsummary>
       <type>
         <v>Phase = atom()</v>
-        <v>StartType = <seealso marker="#type-start_type">start_type()</seealso></v>
+        <v>StartType = <seealso marker="#type-start_type"><c>start_type()</c></seealso></v>
         <v>PhaseArgs = term()</v>
         <v>Pid = pid()</v>
         <v>State = state()</v>
       </type>
       <desc>
-        <p>This function is used to start an application with included
-          applications, when there is a need for synchronization between
+        <p>Starts an application with included
+          applications, when synchronization is needed between
           processes in the different applications during startup.</p>
-        <p>The start phases is defined by the application specification
+        <p>The start phases are defined by the application specification
           key <c>start_phases == [{Phase,PhaseArgs}]</c>. For included
           applications, the set of phases must be a subset of the set of
           phases defined for the including application.</p>
         <p>The function is called for each start phase (as defined for
           the primary application) for the primary application and all
           included applications, for which the start phase is defined.</p>
-        <p>See <c>Module:start/2</c> for a description of
-          <c>StartType</c>.</p>
+        <p>For a description of <c>StartType</c>, see
+	<seealso marker="Module:start/2"><c>Module:start/2</c></seealso>.</p>
       </desc>
     </func>
     <func>
       <name>Module:prep_stop(State) -> NewState</name>
-      <fsummary>Prepare an application for termination</fsummary>
+      <fsummary>Prepare an application for termination.</fsummary>
       <type>
         <v>State = NewState = term()</v>
       </type>
@@ -536,28 +558,26 @@ Nodes = [cp1@cave, {cp2@cave, cp3@cave}]</code>
           the application.</p>
         <p><c>State</c> is the state returned from
           <c>Module:start/2</c>, or <c>[]</c> if no state was returned.
-          <c>NewState</c> is any term and will be passed to
+          <c>NewState</c> is any term and is passed to
           <c>Module:stop/1</c>.</p>
         <p>The function is optional. If it is not defined, the processes
-          will be terminated and then <c>Module:stop(State)</c> is
-          called.</p>
+          are terminated and then <c>Module:stop(State)</c> is called.</p>
       </desc>
     </func>
     <func>
       <name>Module:stop(State)</name>
-      <fsummary>Clean up after termination of an application</fsummary>
+      <fsummary>Clean up after termination of an application.</fsummary>
       <type>
         <v>State = term()</v>
       </type>
       <desc>
         <p>This function is called whenever an application has stopped.
           It is intended to be the opposite of <c>Module:start/2</c>
-          and should do any necessary cleaning up. The return value is
+          and is to do any necessary cleaning up. The return value is
           ignored.</p>
-        <p><c>State</c> is the return value of
-          <c>Module:prep_stop/1</c>, if such a function exists.
-          Otherwise <c>State</c> is taken from the return value of
-          <c>Module:start/2</c>.</p>
+        <p><c>State</c> is the return value of <c>Module:prep_stop/1</c>,
+	  if such a function exists. Otherwise <c>State</c> is taken from
+	  the return value of <c>Module:start/2</c>.</p>
       </desc>
     </func>
     <func>
@@ -572,19 +592,18 @@ Nodes = [cp1@cave, {cp2@cave, cp3@cave}]</code>
       </type>
       <desc>
         <p>This function is called by an application after a code
-          replacement, if there are any changes to the configuration
-          parameters.</p>
-        <p><c>Changed</c> is a list of parameter-value tuples with all
-          configuration parameters with changed values, <c>New</c> is
-          a list of parameter-value tuples with all configuration
-          parameters that have been added, and <c>Removed</c> is a list
-          of all parameters that have been removed.</p>
+          replacement, if the configuration parameters have changed.</p>
+        <p><c>Changed</c> is a list of parameter-value tuples including all
+          configuration parameters with changed values.</p>
+	<p><c>New</c> is a list of parameter-value tuples including all
+	  added configuration parameters.</p>
+	<p><c>Removed</c> is a list of all removed parameters.</p>
       </desc>
     </func>
   </funcs>
 
   <section>
-    <title>SEE ALSO</title>
+    <title>See Also</title>
     <p><seealso marker="doc/design_principles:des_princ">OTP Design Principles</seealso>,
       <seealso marker="kernel_app">kernel(6)</seealso>,
       <seealso marker="app">app(4)</seealso></p>