+static int source_process_msg(
+ pa_msgobject *o,
+ int code,
+ void *data,
+ int64_t offset,
+ pa_memchunk *chunk) {
+
+ struct userdata *u = PA_SOURCE(o)->userdata;
+
+ switch (code) {
+
+ case PA_SOURCE_MESSAGE_GET_LATENCY: {
+ size_t n = 0;
+
+#ifdef FIONREAD
+ int l;
+
+ if (ioctl(u->fd, FIONREAD, &l) >= 0 && l > 0)
+ n = (size_t) l;
+#endif
+
+ *((pa_usec_t*) data) = pa_bytes_to_usec(n, &u->source->sample_spec);
+ return 0;
+ }
+ }
+
+ return pa_source_process_msg(o, code, data, offset, chunk);
+}
+