diff --git a/lib/gtls.c b/lib/gtls.c
index 6e762f161..89a8079bf 100644
--- a/lib/gtls.c
+++ b/lib/gtls.c
@@ -607,9 +607,9 @@ Curl_gtls_connect(struct connectdata *conn,
 
 /* return number of sent (non-SSL) bytes */
 ssize_t Curl_gtls_send(struct connectdata *conn,
-                   int sockindex,
-                   void *mem,
-                   size_t len)
+                       int sockindex,
+                       const void *mem,
+                       size_t len)
 {
   ssize_t rc = gnutls_record_send(conn->ssl[sockindex].session, mem, len);
 
diff --git a/lib/gtls.h b/lib/gtls.h
index 8dc0a30d4..ee560a9cb 100644
--- a/lib/gtls.h
+++ b/lib/gtls.h
@@ -7,7 +7,7 @@
  *                            | (__| |_| |  _ <| |___
  *                             \___|\___/|_| \_\_____|
  *
- * Copyright (C) 1998 - 2007, Daniel Stenberg, <daniel@haxx.se>, et al.
+ * Copyright (C) 1998 - 2008, Daniel Stenberg, <daniel@haxx.se>, et al.
  *
  * This software is licensed as described in the file COPYING, which
  * you should have received as part of this distribution. The terms
@@ -35,7 +35,7 @@ void Curl_gtls_close(struct connectdata *conn, int sockindex);
 
 /* return number of sent (non-SSL) bytes */
 ssize_t Curl_gtls_send(struct connectdata *conn, int sockindex,
-                       void *mem, size_t len);
+                       const void *mem, size_t len);
 ssize_t Curl_gtls_recv(struct connectdata *conn, /* connection data */
                        int num,                  /* socketindex */
                        char *buf,                /* store read data here */