loop: add out_waiting

closes #408

1 files changed, 11 insertions, 0 deletions

diff --git a/serial/urlhandler/protocol_loop.py b/serial/urlhandler/protocol_loop.py
index 526583f..8ac8ddf 100644
--- a/serial/urlhandler/protocol_loop.py
+++ b/serial/urlhandler/protocol_loop.py
@@ -227,6 +227,17 @@ class Serial(SerialBase):
         except queue.Empty:
             pass
 
+    @property
+    def out_waiting(self):
+        """Return how many bytes the in the outgoing buffer"""
+        if not self.is_open:
+            raise PortNotOpenError()
+        if self.logger:
+            # attention the logged value can differ from return value in
+            # threaded environments...
+            self.logger.debug('out_waiting -> {:d}'.format(self.queue.qsize()))
+        return self.queue.qsize()
+
     def _update_break_state(self):
         """\
         Set break: Controls TXD. When active, to transmitting is