--- a/src/cfgfile.cc	Mon Oct 06 00:27:07 2014 +0300
+++ b/src/cfgfile.cc	Mon Oct 06 00:33:26 2014 +0300
@@ -198,6 +198,12 @@
 static const char *confirm_i2e(confirm_t internal);
 
 
+static bool v_is_hex(const char *str)
+{
+    return str[0] == '0' && tolower(str[1]) == 'x';
+}
+
+
 /*
  *        parse_config_file_default - parse the default config file(s)
  *
@@ -489,8 +495,7 @@
                        addition, we don't want any non-zero negative
                        numbers. In terms of regexp, /^(0x)?0*$/i. */
                     if (errno != 0 || neg && !
-                        (strspn(value + 1, "0") == strlen(value + 1) || value[1] == '0' && tolower(value[2]) == 'x'
-                         && strspn(value + 3, "0") == strlen(value + 3)))
+                        (strspn(value + 1, "0") == strlen(value + 1) || v_is_hex(value+1) && strspn(value + 3, "0") == strlen(value + 3)))
                     {
                         err("%s(%u,%d): unsigned integer out of range",
                             filename, lnum, 1 + (int) (value - line));
@@ -686,9 +691,7 @@
                     || neg
                     && !
                     (strspn(value + 1, "0") == strlen(value + 1)
-                     || value[1] == '0'
-                     && tolower(value[2]) == 'x'
-                     && strspn(value + 3, "0") == strlen(value + 3)))
+                     || v_is_hex(value+1) && strspn(value + 3, "0") == strlen(value + 3)))
                 {
                     err("unsigned integer out of range \"%s\"", value);
                     return 1;