Merge pull request #1723 from jhogberg/john/erts/ets-whereis/OTP-14884

Add ets:whereis/1 for resolving table names -> tid()

1 files changed, 27 insertions, 4 deletions

diff --git a/lib/stdlib/doc/src/ets.xml b/lib/stdlib/doc/src/ets.xml
index 1b31a1ec9d..305376a425 100644
--- a/lib/stdlib/doc/src/ets.xml
+++ b/lib/stdlib/doc/src/ets.xml
@@ -487,6 +487,11 @@ Error: fun containing local Erlang function calls
             <p>The pid of the heir of the table, or <c>none</c> if no heir
               is set.</p>
           </item>
+          <tag><c>{id,</c><seealso marker="#type-tid">
+              <c>tid()</c></seealso><c>}</c></tag>
+          <item>
+            <p>The table identifier.</p>
+          </item>
           <tag><c>{keypos, integer() >= 1}</c></tag>
           <item>
             <p>The key position.</p>
@@ -1074,10 +1079,13 @@ ets:select(Table, MatchSpec),</code>
           </item>
           <tag><c>named_table</c></tag>
           <item>
-            <p>If this option is present, name <c><anno>Name</anno></c> is
-              associated with the table identifier. The name can then
-              be used instead of the table identifier in subsequent
-              operations.</p>
+            <p>If this option is present, the table is registered under its
+              <c><anno>Name</anno></c> which can then be used instead of the
+              table identifier in subsequent operations.</p>
+            <p>The function will also return the <c><anno>Name</anno></c>
+              instead of the table identifier. To get the table identifier of a
+              named table, use
+              <seealso marker="#whereis/1"><c>whereis/1</c></seealso>.</p>
           </item>
           <tag><c>{keypos,<anno>Pos</anno>}</c></tag>
           <item>
@@ -2037,6 +2045,21 @@ true</pre>
         </list>
       </desc>
     </func>
+
+    <func>
+      <name name="whereis" arity="1"/>
+      <fsummary>Retrieves the tid() of a named table.</fsummary>
+      <desc>
+        <p>This function returns the
+          <seealso marker="#type-tid"><c>tid()</c></seealso> of the named table
+          identified by <c><anno>TableName</anno></c>, or <c>undefined</c> if
+          no such table exists. The <c>tid()</c> can be used in place of the
+          table name in all operations, which is slightly faster since the name
+          does not have to be resolved on each call.</p>
+        <p>If the table is deleted, the <c>tid()</c> will be invalid even if
+          another named table is created with the same name.</p>
+      </desc>
+    </func>
   </funcs>
 </erlref>