-XBT_PUBLIC int sg_comm_wait_any_for(sg_comm_t* comms, size_t count, double timeout);
-XBT_PUBLIC int sg_comm_wait_any(sg_comm_t* comms, size_t count);
+XBT_PUBLIC size_t sg_comm_wait_all_for(sg_comm_t* comms, size_t count, double timeout);
+XBT_PUBLIC ssize_t sg_comm_wait_any_for(sg_comm_t* comms, size_t count, double timeout);
+XBT_PUBLIC ssize_t sg_comm_wait_any(sg_comm_t* comms, size_t count);