diff --git a/Lib/ruby/ruby.swg b/Lib/ruby/ruby.swg
index d5ca420ee..4b51e3895 100644
--- a/Lib/ruby/ruby.swg
+++ b/Lib/ruby/ruby.swg
@@ -390,7 +390,7 @@ typedef unsigned long VALUE;
 
 %typemap(in) (char *STRING, int LENGTH) {
     $1 = ($1_ltype) StringValuePtr($input);
-    $2 = ($2_ltype) RSTRING($input)->len;
+    $2 = ($2_ltype) StringValueLen($input);
 }
 
 /* Some ANSI C typemaps */
diff --git a/Lib/ruby/rubyhead.swg b/Lib/ruby/rubyhead.swg
index e2af52e1d..ba3880990 100644
--- a/Lib/ruby/rubyhead.swg
+++ b/Lib/ruby/rubyhead.swg
@@ -38,11 +38,6 @@
 #endif
 #endif
 
-/* Ruby 1.8 deprecates STR2CSTR() in favor of StringValuePtr() */
-#ifndef StringValuePtr
-#define StringValuePtr(x) STR2CSTR((x))
-#endif
-
 /*
  * Need to be very careful about how these macros are defined, especially
  * when compiling C++ code or C code with an ANSI C compiler.
@@ -80,3 +75,28 @@ typedef struct {
   void  (*mark)(void *);
   void  (*destroy)(void *);
 } swig_class;
+
+/* Don't use for expressions have side effect */
+#ifndef RB_STRING_VALUE
+#define RB_STRING_VALUE(s) (TYPE(s) == T_STRING ? (s) : (*(volatile VALUE *)&(s) = rb_str_to_str(s)))
+#endif
+#ifndef StringValue
+#define StringValue(s) RB_STRING_VALUE(s)
+#endif
+#ifndef StringValuePtr
+#define StringValuePtr(s) RSTRING(RB_STRING_VALUE(s))->ptr
+#endif
+#ifndef StringValueLen
+#define StringValueLen(s) RSTRING(RB_STRING_VALUE(s))->len
+#endif
+#ifndef SafeStringValue
+#define SafeStringValue(v) do {\
+    StringValue(v);\
+    rb_check_safe_str(v);\
+} while (0)
+#endif
+
+#ifndef HAVE_RB_DEFINE_ALLOC_FUNC
+#define rb_undef_alloc_func(klass) rb_undef_method(CLASS_OF(klass), "new")
+#endif
+
diff --git a/Source/Modules/ruby.cxx b/Source/Modules/ruby.cxx
index e6993e800..52ae0b021 100644
--- a/Source/Modules/ruby.cxx
+++ b/Source/Modules/ruby.cxx
@@ -458,8 +458,8 @@ public:
 
   void create_command(Node *n, const String_or_char *iname) {
 
+    String *alloc_func_name = Swig_name_wrapper(iname);
     String *wname = Swig_name_wrapper(iname);
-    String *wname2 = Swig_name_wrapper(iname);
     if (CPlusPlus) {
       Insert(wname,0,"VALUEFUNC(");
       Append(wname,")");
@@ -479,13 +479,11 @@ public:
 	     iname, "\", ", wname, ", -1);\n", NIL);
       break;
     case CONSTRUCTOR_ALLOCATE:
-      Printv(s, "#ifdef HAVE_RB_DEFINE_ALLOC_FUNC\n", NIL);
-      Printv(s, tab4, "rb_define_alloc_func(", klass->vname,
-	     ", ", wname2, ");\n", NIL);
-      Printv(s, "#else\n", NIL);
-      Printv(s, tab4, "rb_define_singleton_method(", klass->vname,
-	     ", \"new\", ", wname, ", -1);\n", NIL);
-      Printv(s, "#endif\n", NIL);
+      Printf(s, "#ifdef HAVE_RB_DEFINE_ALLOC_FUNC\n");
+      Printv(s, tab4, "rb_define_alloc_func(", klass->vname, ", ", alloc_func_name, ");\n", NIL);
+      Printf(s, "#else\n");
+      Printv(s, tab4, "rb_define_singleton_method(", klass->vname, ", \"new\", ", wname, ", -1);\n", NIL); 
+      Printf(s, "#endif\n");
       Replaceall(klass->init,"$allocator", s);
       break;
     case CONSTRUCTOR_INITIALIZE:
@@ -516,7 +514,7 @@ public:
     Delete(temp);
     Delete(s);
     Delete(wname);
-    Delete(wname2);
+    Delete(alloc_func_name);
   }
   
   /* ---------------------------------------------------------------------
@@ -1342,10 +1340,7 @@ public:
     Printv(f_header, klass->header,NIL);
 
     String *s = NewString("");
-    Printv(s, "#ifndef HAVE_RB_DEFINE_ALLOC_FUNC\n", NIL);
-    Printv(s, tab4, "rb_undef_method(CLASS_OF(", klass->vname,
-	   "), \"new\");\n", NIL);
-    Printv(s, "#endif\n", NIL);
+    Printv(s, tab4, "rb_undef_alloc_func(", klass->vname, ");\n", NIL);
     Replaceall(klass->init,"$allocator", s);
     Replaceall(klass->init,"$initializer", "");
     Replaceall(klass->init,"$super", "rb_cObject");