erts: Document external format for maps (MAP_EXT)

1 files changed, 31 insertions, 1 deletions

diff --git a/erts/doc/src/erl_ext_dist.xml b/erts/doc/src/erl_ext_dist.xml
index f91ed78122..9a53f3f829 100644
--- a/erts/doc/src/erl_ext_dist.xml
+++ b/erts/doc/src/erl_ext_dist.xml
@@ -5,7 +5,7 @@
   <header>
     <copyright>
       <year>2007</year>
-      <year>2013</year>
+      <year>2014</year>
       <holder>Ericsson AB, All Rights Reserved</holder>
     </copyright>
     <legalnotice>
@@ -573,6 +573,36 @@
     </section>
 
     <section>
+      <marker id="MAP_EXT"/>
+      <title>MAP_EXT</title>
+
+	<table align="left">
+	  <row>
+	    <cell align="center">1</cell>
+	    <cell align="center">4</cell>
+	    <cell align="center">N</cell>
+	    <cell align="center">M</cell>
+	  </row>
+	  <row>
+	    <cell align="center">116</cell>
+	    <cell align="center">Arity</cell>
+	    <cell align="center">Keys</cell>
+	    <cell align="center">Values</cell>
+	  </row>
+	<tcaption></tcaption></table>
+	<p>
+	  <c>MAP_EXT</c> encodes a map. The <c>Arity</c> field is an unsigned
+	  4 byte integer in big endian format that determines the number of
+	  key-value pairs in the map. All key terms follow in the <c>Keys</c>
+	  section and then all value terms in the <c>Values</c> section. Keys
+	  and values are paired according to order; first key with first value
+	  and so on. Duplicate keys are <em>not allowed</em> within the same
+	  map.
+	</p>
+	<p><em>Since: </em>OTP 17.0</p>
+    </section>
+
+    <section>
       <marker id="NIL_EXT"/>
       <title>NIL_EXT</title>