diff --git a/src/bookmarks/bookmarks.c b/src/bookmarks/bookmarks.c
index 0b3ea6ed..524ac43a 100644
--- a/src/bookmarks/bookmarks.c
+++ b/src/bookmarks/bookmarks.c
@@ -435,7 +435,7 @@ add_bookmark(struct bookmark *root, int place, const char *title,
  * @see add_bookmark() */
 struct bookmark *
 add_bookmark_cp(struct bookmark *root, int place, int codepage,
-		char *title, char *url)
+		const char *title, const char *url)
 {
 	const int utf8_cp = get_cp_index("UTF-8");
 	struct conv_table *table;
diff --git a/src/bookmarks/bookmarks.h b/src/bookmarks/bookmarks.h
index 6ea9736b..f90cc03c 100644
--- a/src/bookmarks/bookmarks.h
+++ b/src/bookmarks/bookmarks.h
@@ -50,7 +50,7 @@ int bookmarks_are_dirty(void);
 void delete_bookmark(struct bookmark *);
 struct bookmark *add_bookmark(struct bookmark *, int, const char *, const char *);
 struct bookmark *add_bookmark_cp(struct bookmark *, int, int,
-				 char *, char *);
+				 const char *, const char *);
 struct bookmark *get_bookmark_by_name(struct bookmark *folder,
                                       char *title);
 struct bookmark *get_bookmark(char *url);
diff --git a/src/intl/charsets.c b/src/intl/charsets.c
index f9d72892..db2aabfd 100644
--- a/src/intl/charsets.c
+++ b/src/intl/charsets.c
@@ -1271,7 +1271,7 @@ end:
 
 char *
 convert_string(struct conv_table *convert_table,
-	       char *chars2, int charslen2, int cp,
+	       const char *chars2, int charslen2, int cp,
 	       enum convert_string_mode mode, int *length,
 	       void (*callback)(void *data, char *buf, int buflen),
 	       void *callback_data)
diff --git a/src/intl/charsets.h b/src/intl/charsets.h
index 55ad6be9..ddaa9eea 100644
--- a/src/intl/charsets.h
+++ b/src/intl/charsets.h
@@ -119,7 +119,7 @@ const char *get_entity_string(const char *str,
  * it each few bytes instead and always returns NULL (@length is undefined).
  * Note that it's ok not to care and pass NULL as @length. */
 char *convert_string(struct conv_table *convert_table,
-			      char *chars, int charslen, int cp,
+			      const char *chars, int charslen, int cp,
 			      enum convert_string_mode mode, int *length,
 			      void (*callback)(void *data, char *buf, int buflen),
 			      void *callback_data);