Fix grammar

diff --git a/doc/src/sgml/extend.sgml b/doc/src/sgml/extend.sgml
index 246451a42eb1371abfa5afb62b486395adb9e690..1c7da4a2abb76c3461a36846fcc83a5627ea5904 100644 (file)
--- a/doc/src/sgml/extend.sgml
+++ b/doc/src/sgml/extend.sgml
@@ -320,7 +320,7 @@
      
       
        If calling backend functions from C++ code, be sure that the
-       C++ call stack contains only plain old data structure
+       C++ call stack contains only plain old data structures
        (POD).  This is necessary because backend errors
        generate a distant longjump() that does not properly
        unroll a C++ call stack with non-POD objects.