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-rw-r--r--lib/stdlib/doc/src/gen_statem.xml18
1 files changed, 13 insertions, 5 deletions
diff --git a/lib/stdlib/doc/src/gen_statem.xml b/lib/stdlib/doc/src/gen_statem.xml
index c57a31fa21..ed44eef912 100644
--- a/lib/stdlib/doc/src/gen_statem.xml
+++ b/lib/stdlib/doc/src/gen_statem.xml
@@ -1262,9 +1262,9 @@ handle_event(_, _, State, Data) ->
<v>&nbsp;&nbsp;Vsn = term()</v>
<v>OldState = NewState = term()</v>
<v>Extra = term()</v>
- <v>Result = {NewCallbackMode,NewState,NewData} | Reason</v>
+ <v>Result = {CallbackMode,NewState,NewData} | Reason</v>
<v>
- NewCallbackMode =
+ CallbackMode =
<seealso marker="#type-callback_mode">callback_mode()</seealso>
</v>
<v>
@@ -1321,11 +1321,19 @@ handle_event(_, _, State, Data) ->
<p>
If successful, the function must return the updated
internal state in an
- <c>{NewCallbackMode,NewState,NewData}</c> tuple.
+ <c>{CallbackMode,NewState,NewData}</c> tuple.
</p>
<p>
- If the function returns <c>Reason</c>, the ongoing
- upgrade fails and rolls back to the old release.</p>
+ If the function returns a failure <c>Reason</c>, the ongoing
+ upgrade fails and rolls back to the old release.
+ Note that <c>Reason</c> can not be a 3-tuple since that
+ will be regarded as a
+ <c>{CallbackMode,NewState,NewData}</c> tuple,
+ and that a tuple matching <c>{ok,_}</c>
+ is an invalid failure <c>Reason</c>.
+ It is recommended to use an atom as <c>Reason</c> since
+ it will be wrapped in an <c>{error,Reason}</c> tuple.
+ </p>
<p>
This function can use
<seealso marker="erts:erlang#throw/1"><c>erlang:throw/1</c></seealso>