posix: fix return value of write, fixes #189
diff --git a/serial/serialposix.py b/serial/serialposix.py
index 980430c..dcc71a0 100644
--- a/serial/serialposix.py
+++ b/serial/serialposix.py
@@ -516,7 +516,7 @@
if not self.is_open:
raise portNotOpenError
d = to_bytes(data)
- tx_len = len(d)
+ tx_len = length = len(d)
timeout = Timeout(self._write_timeout)
while tx_len > 0:
try:
@@ -555,7 +555,7 @@
# still calculate and check timeout
if timeout.expired():
raise writeTimeoutError
- return len(d)
+ return length - len(d)
def flush(self):
"""\