x);
SCM_API SCM scm_string_p (SCM x);
SCM_API SCM scm_string (SCM chrs);
SCM_API SCM scm_make_string (SCM k, SCM chr);
SCM_API SCM scm_string_length (SCM str);
SCM_API SCM scm_string_utf8_length (SCM str);
SCM_API SCM scm_string_bytes_per_char (SCM str);
SCM_API SCM scm_string_ref (SCM str, SCM k);
SCM_API SCM scm_string_set_x (SCM str, SCM k, SCM chr);
SCM_API SCM scm_substring (SCM str, SCM start, SCM end);
SCM_API SCM scm_substring_read_only (SCM str, SCM start, SCM end);
SCM_API SCM scm_substring_shared (SCM str, SCM start, SCM end);
SCM_API SCM scm_substring_copy (SCM str, SCM start, SCM end);
SCM_API SCM scm_string_append (SCM args);

SCM_API SCM scm_from_stringn (const char *str, size_t len, const char *encoding,
                              scm_t_string_failed_conversion_handler handler);
SCM_API SCM scm_c_make_string (size_t len, SCM chr);
SCM_API size_t scm_c_string_length (SCM str);
SCM_API size_t scm_c_string_utf8_length (SCM str);
SCM_API size_t scm_c_symbol_length (SCM sym);
SCM_API SCM scm_c_string_ref (SCM str, size_t pos);
SCM_API void scm_c_string_set_x (SCM str, size_t pos, SCM chr);
SCM_API SCM scm_c_substring (SCM str, size_t start, size_t end);
SCM_API SCM scm_c_substring_read_only (SCM str, size_t start, size_t end);
SCM_API SCM scm_c_substring_shared (SCM str, size_t start, size_t end);
SCM_API SCM scm_c_substring_copy (SCM str, size_t start, size_t end);

/* Use locale encoding for user input, user output, or interacting with
   the C library.  Use latin1 for ASCII, and for literals in source
   code.  Use utf8 for interaction with modern libraries which deal in
   UTF-8.  Otherwise use scm_to_stringn or scm_from_stringn with a
   specific encoding. */

SCM_API SCM scm_from_locale_string (const char *str);
SCM_API SCM scm_from_locale_stringn (const char *str, size_t len);
SCM_API SCM scm_take_locale_string (char *str);
SCM_API SCM scm_take_locale_stringn (char *str, size_t len);
SCM_API char *scm_to_locale_string (SCM str);
SCM_API char *scm_to_locale_stringn (SCM str, size_t *lenp);

SCM_API SCM scm_from_latin1_string (const char *str);
SCM_API SCM scm_from_latin1_stringn (const char *str, size_t len);
SCM_API char *scm_to_latin1_string (SCM str);
SCM_API char *scm_to_latin1_stringn (SCM str, size_t *lenp);

SCM_API char *scm_to_utf8_string (SCM str);
SCM_API char *scm_to_utf8_stringn (SCM str, size_t *lenp);
SCM_API SCM scm_from_utf8_string (const char *str);
SCM_API SCM scm_from_utf8_stringn (const char *str, size_t len);

SCM_API scm_t_wchar *scm_to_utf32_string (SCM str);
SCM_API scm_t_wchar *scm_to_utf32_stringn (SCM str, size_t *lenp);
SCM_API SCM scm_from_utf32_string (const scm_t_wchar *str);
SCM_API SCM scm_from_utf32_stringn (const scm_t_wchar *str, size_t len);

SCM_API char *scm_to_port_string (SCM str, SCM port);
SCM_API char *scm_to_port_stringn (SCM str, size_t *lenp, SCM port);
SCM_API SCM scm_from_port_string (const char *str, SCM port);
SCM_API SCM scm_from_port_stringn (const char *str, size_t len, SCM port);

SCM_API char *scm_to_stringn (SCM str, size_t *lenp, const char *encoding,
                              scm_t_string_failed_conversion_handler handler);
SCM_API size_t scm_to_locale_stringbuf (SCM str, char *buf, size_t max_len);

SCM_API SCM scm_string_normalize_nfd (SCM str);
SCM_API SCM scm_string_normalize_nfkd (SCM str);
SCM_API SCM scm_string_normalize_nfc (SCM str);
SCM_API SCM scm_string_normalize_nfkc (SCM str);

SCM_API SCM scm_makfromstrs (int argc, char **argv);