diff --git a/src/reader.c b/src/reader.c
index b74b661..73d6754 100644
--- a/src/reader.c
+++ b/src/reader.c
@@ -1940,7 +1940,7 @@ scm_to_reader (SCM reader)
 struct scm_reader_flag_entry;
 
 const struct scm_reader_flag_entry *
-_scm_to_make_reader_flag (const char *, unsigned int);
+_scm_to_make_reader_flag (register const char *str, register size_t len);
 
 /* Include the automatically-generated perfect hash function.  */
 #include "make-reader-flags.c"
diff --git a/src/token-readers.c b/src/token-readers.c
index c0a9057..5181347 100644
--- a/src/token-readers.c
+++ b/src/token-readers.c
@@ -1139,7 +1139,7 @@ scm_read_skribe_exp (scm_t_wchar chr, SCM port, scm_reader_t reader,
 /* Directory of standard token readers.  */
 
 extern const struct scm_token_reader_entry *
-_scm_token_reader_lookup (const char *, unsigned int);
+_scm_token_reader_lookup (register const char *str, register size_t len);
 
 #include <string.h>
 #include "token-reader-lookup.c"