* Access errno

Author: smurfix

debian/changelog

@@ -1,3 +1,9 @@
+trio-gpio (0.2.2-1) unstable; urgency=medium
+
+  * Access errno
+
+ -- Matthias Urlichs <matthias@urlichs.de>  Mon, 11 Jun 2018 08:29:53 +0200
+
 trio-gpio (0.2.1-1) unstable; urgency=medium
 
   * Allow (and prefer) the GPIO chip label instead of its number.

trio_gpio/gpio.py

@@ -137,6 +137,8 @@ def _enter_io(self):
             self.__exit__()
             raise RuntimeError("Unknown direction", r)
         if r != 0:
+            if r < 0:
+                r = gpio.ffi.errno
             self.__exit__()
             raise OSError("unable to set direction", r)
         self._state = _IN_IO
@@ -149,7 +151,7 @@ def _enter_ev(self):
         req.flags = self._flags
 
         if gpio.lib.gpiod_line_request(self._line, req, 0) != 0:
-            raise OSError("unable to request event monitoring")
+            raise OSError("unable to request event monitoring", gpio.ffi.errno)
         self._state = _IN_EV
 
     def __exit__(self, *tb):
@@ -277,7 +279,9 @@ async def __anext__(self):
         self._is_open()
         r = gpio.lib.gpiod_line_event_read_fd(fd, ev)
         if r != 0:
-            raise OSError("unable to read update")
+            if r < 0:
+                r = gpio.ffi.errno
+            raise OSError("unable to read update", r)
         return Event(ev)
 
     async def aclose(self):