-extern ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len);
-extern ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len);
-extern ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd);
-extern ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd);
+LTTNG_HIDDEN
+ssize_t ustcomm_recv_unix_sock(int sock, void *buf, size_t len);
+LTTNG_HIDDEN
+ssize_t ustcomm_send_unix_sock(int sock, const void *buf, size_t len);
+LTTNG_HIDDEN
+ssize_t ustcomm_send_fds_unix_sock(int sock, int *fds, size_t nb_fd);
+LTTNG_HIDDEN
+ssize_t ustcomm_recv_fds_unix_sock(int sock, int *fds, size_t nb_fd);