Index: hex.hpp
===================================================================
--- hex.hpp	(revision 81324)
+++ hex.hpp	(working copy)
@@ -69,19 +69,15 @@
         return std::copy ( res, res + num_hex_digits, out );
         }
 
-// this needs to be in an un-named namespace because it is not a template
-// and might get included in several compilation units. This could cause
-// multiple definition errors at link time.
-    namespace {
-    unsigned hex_char_to_int ( char c ) {
-        if ( c >= '0' && c <= '9' ) return c - '0';
-        if ( c >= 'A' && c <= 'F' ) return c - 'A' + 10;
-        if ( c >= 'a' && c <= 'f' ) return c - 'a' + 10;
-        BOOST_THROW_EXCEPTION (non_hex_input() << bad_char (c));
-        return 0;     // keep dumb compilers happy
+    template <typename T> T hex_char_to_int ( T c ) {
+		T r;
+        if      ( c >= static_cast<T>('0') && c <= static_cast<T>('9') ) r = c - static_cast<T>('0');
+        else if ( c >= static_cast<T>('A') && c <= static_cast<T>('F') ) r = c - static_cast<T>('A') + 10;
+        else if ( c >= static_cast<T>('a') && c <= static_cast<T>('f') ) r = c - static_cast<T>('a') + 10;
+		else    BOOST_THROW_EXCEPTION (non_hex_input() << (boost::error_info<struct bad_char_,T> (c)));
+        return r;
         }
-    }    
-
+ 
 //  My own iterator_traits class.
 //  It is here so that I can "reach inside" some kinds of output iterators
 //      and get the type to write.
@@ -134,7 +130,7 @@
         for ( std::size_t i = 0; i < 2 * sizeof ( T ); ++i, ++first ) {
             if ( pred ( first, last )) 
                 BOOST_THROW_EXCEPTION (not_enough_input ());
-            res = ( 16 * res ) + hex_char_to_int (static_cast<char> (*first));
+            res = ( 16 * res ) + hex_char_to_int (*first);
             }
         
         *out = res;