+int ParseInt(const std::string & str, int * val);
+int ParseUnsigned(const std::string & str, unsigned * val);
+int ParseIntInRange(const std::string & str, int min, int max, int * val);
+int ParseUnsignedInRange(const std::string & str, unsigned min,
+ unsigned max, unsigned * val);
+int ParseYesNo(const std::string & str, bool * val);
+