diff --git a/libsofia-sip-ua/tport/sofia-sip/tport.h b/libsofia-sip-ua/tport/sofia-sip/tport.h
index 89d6a47ace9fe83dc0e0f68dcfb3db30c0b23228..f863bef50154d7e602921b3146546ef908d87f8a 100644
--- a/libsofia-sip-ua/tport/sofia-sip/tport.h
+++ b/libsofia-sip-ua/tport/sofia-sip/tport.h
@@ -210,7 +210,7 @@ TPORT_DLL tport_t *tport_tsend(tport_t *, msg_t *, tp_name_t const *,
 TPORT_DLL int tport_tqueue(tport_t *, msg_t *, tag_type_t, tag_value_t, ...);
 
 /** Return number of queued messages. */
-TPORT_DLL int tport_queuelen(tport_t const *self);
+TPORT_DLL isize_t tport_queuelen(tport_t const *self);
 
 /** Send a queued message (and queue another, if required). */
 TPORT_DLL int tport_tqsend(tport_t *, msg_t *, msg_t *, 
diff --git a/libsofia-sip-ua/tport/tport.c b/libsofia-sip-ua/tport/tport.c
index 9e03e01b12dd3329d72671eaac770b5eb63f8aa5..80d8ed19abb3cd2fa3f9c297efece0997f493917 100644
--- a/libsofia-sip-ua/tport/tport.c
+++ b/libsofia-sip-ua/tport/tport.c
@@ -3122,7 +3122,8 @@ int tport_send_msg(tport_t *self, msg_t *msg,
 		   struct sigcomp_compartment *cc)
 {
   msg_iovec_t *iov, auto_iov[40];
-  size_t iovlen, iovused, i, total, n;
+  size_t iovlen, iovused, i, total;
+  ssize_t n;
   ssize_t nerror;
   int sdwn_after, close_after;
   su_time_t now;