1 files changed, 6 insertions, 4 deletions

diff --git a/src/coding.h b/src/coding.h
index 500f02acf32..677004ce523 100644
--- a/src/coding.h
+++ b/src/coding.h
@@ -611,9 +611,9 @@ struct coding_system
 #endif /* !WINDOWSNT */
 
 /* Extern declarations.  */
-extern int decode_coding P_ ((struct coding_system *, unsigned char *,
+extern int decode_coding P_ ((struct coding_system *, const unsigned char *,
                               unsigned char *, int, int));
-extern int encode_coding P_ ((struct coding_system *, unsigned char *,
+extern int encode_coding P_ ((struct coding_system *, const unsigned char *,
                               unsigned char *, int, int));
 extern void coding_save_composition P_ ((struct coding_system *, int, int,
                                          Lisp_Object));
@@ -631,8 +631,10 @@ extern Lisp_Object run_pre_post_conversion_on_str P_ ((Lisp_Object,
                                                        int));
 extern int decoding_buffer_size P_ ((struct coding_system *, int));
 extern int encoding_buffer_size P_ ((struct coding_system *, int));
-extern void detect_coding P_ ((struct coding_system *, unsigned char *, int));
-extern void detect_eol P_ ((struct coding_system *, unsigned char *, int));
+extern void detect_coding P_ ((struct coding_system *, const unsigned char *,
+                               int));
+extern void detect_eol P_ ((struct coding_system *, const unsigned char *,
+                            int));
 extern int setup_coding_system P_ ((Lisp_Object, struct coding_system *));
 extern Lisp_Object code_convert_string P_ ((Lisp_Object,
                                             struct coding_system *, int, int));