+/// convert \p s from the encoding of the locale to ucs4.
+docstring const from_local8bit(std::string const & s);
+
+/// Exception thrown by to_local8bit if the string could not be converted
+class to_local8bit_failure : public std::bad_cast {
+public:
+ to_local8bit_failure() throw() : std::bad_cast() {}
+ virtual ~to_local8bit_failure() throw() {}
+ virtual const char* what() const throw();
+};
+
+/**
+ * Convert \p s from ucs4 to the encoding of the locale.
+ * This may fail and throw an exception, the caller is expected to act
+ * appropriately.
+ */
+std::string const to_local8bit(docstring const & s);
+
+/// convert \p s from the encoding of the file system to ucs4.
+docstring const from_filesystem8bit(std::string const & s);
+
+/// convert \p s from ucs4 to the encoding of the file system.
+std::string const to_filesystem8bit(docstring const & s);
+
+/// normalize \p s to precomposed form c
+docstring const normalize_c(docstring const & s);