int str2x(const std::string & str, unsigned & x);
int str2x(const std::string & str, long & x);
int str2x(const std::string & str, unsigned long & x);
int str2x(const std::string & str, unsigned & x);
int str2x(const std::string & str, long & x);
int str2x(const std::string & str, unsigned long & x);