diff --git a/src/tool_urlglob.c b/src/tool_urlglob.c
index da073d0393..bd03c9e6dc 100644
--- a/src/tool_urlglob.c
+++ b/src/tool_urlglob.c
@@ -489,7 +489,7 @@ bool glob_inuse(struct URLGlob *glob)
   return glob->palloc ? TRUE : FALSE;
 }
 
-CURLcode glob_url(struct URLGlob *glob, char *url, curl_off_t *urlnum,
+CURLcode glob_url(struct URLGlob *glob, const char *url, curl_off_t *urlnum,
                   FILE *error)
 {
   /*
diff --git a/src/tool_urlglob.h b/src/tool_urlglob.h
index d0a807f796..84913d8f63 100644
--- a/src/tool_urlglob.h
+++ b/src/tool_urlglob.h
@@ -71,9 +71,11 @@ struct URLGlob {
   size_t pos;        /* column position of error or 0 */
 };
 
-CURLcode glob_url(struct URLGlob *, char *, curl_off_t *, FILE *);
-CURLcode glob_next_url(char **, struct URLGlob *);
-CURLcode glob_match_url(char **, const char *, struct URLGlob *);
+CURLcode glob_url(struct URLGlob *glob, const char *url, curl_off_t *urlnum,
+                  FILE *error);
+CURLcode glob_next_url(char **globbed, struct URLGlob *glob);
+CURLcode glob_match_url(char **output, const char *filename,
+                        struct URLGlob *glob);
 void glob_cleanup(struct URLGlob *glob);
 bool glob_inuse(struct URLGlob *glob);