Index: nonfinite_num_facets.hpp
===================================================================
--- nonfinite_num_facets.hpp	(revision 76772)
+++ nonfinite_num_facets.hpp	(working copy)
@@ -118,17 +118,26 @@
           break;
 
         case FP_ZERO:
-          if(flags_ & signed_zero) {
+          if(flags_ & signed_zero)
+          { // Distinguish between positive and negative zero.
             if((boost::math::signbit)(val))
+            {
               put_num_and_fill(it, iosb, "-", "0", fill);
+            }
             else if(iosb.flags() & std::ios_base::showpos)
+            {
               put_num_and_fill(it, iosb, "+", "0", fill);
+            }
             else
+            { // No sign.
               put_num_and_fill(it, iosb, "", "0", fill);
+            }
           }
-          else
-            put_num_and_fill(it, iosb, "", "0", fill);
-          break;
+          //else
+          //{ // 
+          //  put_num_and_fill(it, iosb, "", "0", fill);
+          //}
+          //break;
 
         default:
           it = std::num_put<CharType, OutputIterator>::do_put(