Merge branch 'nox/ets-update_counter-4'

* nox/ets-update_counter-4:
  Create new BIF ets:update_counter/4
  Allow 4-ary BIFs

OTP-12563

1 files changed, 15 insertions, 1 deletions

diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml
index 902a921fbf..6b9524ef63 100644
--- a/lib/stdlib/doc/src/ets.xml
+++ b/lib/stdlib/doc/src/ets.xml
@@ -1618,14 +1618,18 @@ true</pre>
     </func>
     <func> 
       <name name="update_counter" arity="3" clause_i="1"/>
+      <name name="update_counter" arity="4" clause_i="1"/>
       <name name="update_counter" arity="3" clause_i="2"/>
+      <name name="update_counter" arity="4" clause_i="2"/>
       <name name="update_counter" arity="3" clause_i="3"/>
+      <name name="update_counter" arity="4" clause_i="3"/>
       <type variable="Tab"/>
       <type variable="Key"/>
       <type variable="UpdateOp" name_i="1"/>
       <type variable="Pos" name_i="1"/>
       <type variable="Threshold" name_i="1"/>
       <type variable="SetValue" name_i="1"/>
+      <type variable="Default"/>
       <fsummary>Update a counter object in an ETS table.</fsummary>
       <desc>
         <p>This function provides an efficient way to update one or more 
@@ -1667,12 +1671,22 @@ true</pre>
           <seealso marker="#lookup/2">lookup/2</seealso> and 
           <seealso marker="#new/2">new/2</seealso>
           for details on the difference).</p>
+        <p>If a default object <c><anno>Default</anno></c> is given, it is used
+          as the object to be updated if the key is missing from the table. The
+          value in place of the key is ignored and replaced by the proper key
+          value. The return value is as if the default object had not been used,
+          that is a single updated element or a list of them.</p>
         <p>The function will fail with reason <c>badarg</c> if:</p>
         <list type="bulleted">
           <item>the table is not of type <c>set</c> or
           <c>ordered_set</c>,</item>
-          <item>no object with the right key exists,</item>
+          <item>no object with the right key exists and no default object were
+            supplied,</item>
           <item>the object has the wrong arity,</item>
+          <item>the default object arity is smaller than
+            <c><![CDATA[<keypos>]]></c></item>
+          <item>any field from the default object being updated is not an
+            integer</item>
           <item>the element to update is not an integer,</item>
           <item>the element to update is also the key, or,</item>
           <item>any of <c><anno>Pos</anno></c>, <c><anno>Incr</anno></c>, <c><anno>Threshold</anno></c> or