-extern void html_status(int code, const char *msg, int more_headers);
-extern void html_txt(char *txt);
-extern void html_ntxt(int len, char *txt);
-extern void html_attr(char *txt);
-extern void html_url_arg(char *txt);
-extern void html_hidden(char *name, char *value);
-extern void html_option(char *value, char *text, char *selected_value);
-extern void html_link_open(char *url, char *title, char *class);
+
+__attribute__((format (printf,1,2)))
+extern void html_txtf(const char *format,...);
+
+__attribute__((format (printf,1,0)))
+extern void html_vtxtf(const char *format, va_list ap);
+
+__attribute__((format (printf,1,2)))
+extern void html_attrf(const char *format,...);
+
+extern void html_txt(const char *txt);
+extern ssize_t html_ntxt(const char *txt, size_t len);
+extern void html_attr(const char *txt);
+extern void html_url_path(const char *txt);
+extern void html_url_arg(const char *txt);
+extern void html_header_arg_in_quotes(const char *txt);
+extern void html_hidden(const char *name, const char *value);
+extern void html_option(const char *value, const char *text, const char *selected_value);
+extern void html_intoption(int value, const char *text, int selected_value);
+extern void html_link_open(const char *url, const char *title, const char *class);