Index: generator.hpp
===================================================================
--- generator.hpp	(revision 83422)
+++ generator.hpp	(working copy)
@@ -9,6 +9,7 @@
 #include "char_traits.hpp"
 // memcmp()
 #include <cstring>
+#include <limits>
 #include "partition/charset.hpp"
 #include "partition/equivset.hpp"
 #include <memory>
@@ -560,7 +561,7 @@
 
         if (token_._negated)
         {
-            CharT curr_char_ = sizeof (CharT) == 1 ? -128 : 0;
+            CharT curr_char_ = (std::numeric_limits<CharT>::min)();
             std::size_t i_ = 0;
 
             while (curr_ < chars_end_)
Index: string_token.hpp
===================================================================
--- string_token.hpp	(revision 83422)
+++ string_token.hpp	(working copy)
@@ -7,6 +7,7 @@
 #define BOOST_LEXER_STRING_TOKEN_HPP
 
 #include <algorithm>
+#include <limits>
 #include "size_t.hpp"
 #include "consts.hpp" // num_chars, num_wchar_ts
 #include <string>
@@ -71,7 +72,7 @@
     {
         const std::size_t max_chars_ = sizeof (CharT) == 1 ?
             num_chars : num_wchar_ts;
-        CharT curr_char_ = sizeof (CharT) == 1 ? -128 : 0;
+        CharT curr_char_ = (std::numeric_limits<CharT>::min)();
         string temp_;
         const CharT *curr_ = _charset.c_str ();
         const CharT *chars_end_ = curr_ + _charset.size ();