Add a bit of documentation about restart_application (#1582)

It is now explicitly stated that if the application type is `load`, the
application will not actually be restarted by the `restart_application`
instruction in relup, even if it is currently running. It will only be stopped
and re-loaded.

1 files changed, 11 insertions, 3 deletions

diff --git a/lib/sasl/doc/src/appup.xml b/lib/sasl/doc/src/appup.xml
index a43a966dcb..d9d339884f 100644
--- a/lib/sasl/doc/src/appup.xml
+++ b/lib/sasl/doc/src/appup.xml
@@ -249,9 +249,17 @@
     <pre>
 {restart_application, Application}
   Application = atom()</pre>
-    <p>Restarting an application means that the application is
-      stopped and then started again, similar to using the instructions
-      <c>remove_application</c> and <c>add_application</c> in sequence.</p>
+    <p>Restarting an application means that the application is stopped
+    and then started again, similar to using the instructions
+    <c>remove_application</c> and <c>add_application</c> in sequence.
+    Note that, even if the application has been started before the
+    release upgrade is performed, <c>restart_application</c> may only
+    <c>load</c> it rather than <c>start</c> it, depending on the
+    application's <c>start type</c>:
+    If <c>Type = load</c>, the application is only loaded.
+    If <c>Type = none</c>, the application is not loaded and not
+    started, although the code for its modules is loaded.
+    </p>
     </section>
 
     <section>