HPCC-10140 Document Virtual Logicalfilename

Signed-off-by: JamesDeFabia <James.Defabia@LexisNexis.com>

docs/ECLLanguageReference/ECLR_mods/RecordStructure.xml

@@ -548,6 +548,14 @@ END;</programlisting>
           <row>
             <entry></entry>
 
+            <entry><emphasis role="bold"> { VIRTUAL<indexterm>
+                <primary>Virtual logicalfilename</primary>
+              </indexterm>( logicalfilename ) }</emphasis></entry>
+          </row>
+
+          <row>
+            <entry></entry>
+
             <entry><emphasis role="bold"> { BLOB<indexterm>
                 <primary>BLOB in INDEX</primary>
               </indexterm> }</emphasis></entry>
@@ -645,6 +653,16 @@ END;</programlisting>
           </row>
 
           <row>
+            <entry><emphasis role="bold">{ VIRTUAL( logicalfilename )
+            }</emphasis></entry>
+
+            <entry>Specifies the logical file name of the distributed file.
+            This must be a STRING field and must be the last field, because it
+            only truly exists when the file is loaded into memory from disk
+            (hence, the “virtual”).</entry>
+          </row>
+
+          <row>
             <entry><emphasis role="bold">{ BLOB }</emphasis></entry>
 
             <entry>Specifies the field is stored separately from the leaf node