#811: move DLL check logic in _pswindows.py

psutil/__init__.py

@@ -123,24 +123,7 @@
             pass
 
 elif WINDOWS:
-    try:
-        from . import _pswindows as _psplatform
-    except ImportError as err:
-        if sys.getwindowsversion()[0] < 6:
-            # We may get here if:
-            # 1) we are on an old Windows version
-            # 2) psutil was installed via pip + wheel
-            # See: https://github.com/giampaolo/psutil/issues/811
-            # It must be noted that psutil can still (kind of) work
-            # on outdated systems if compiled / installed from sources,
-            # but if we get here it means this this was a wheel (or exe).
-            msg = "this Windows version is too old (< Windows Vista); "
-            msg += "psutil 3.4.2 is the latest version which supports Windows "
-            msg += "2000, XP and 2003 server"
-            raise RuntimeError(msg)
-        else:
-            raise
-
+    from . import _pswindows as _psplatform
     from ._psutil_windows import ABOVE_NORMAL_PRIORITY_CLASS  # NOQA
     from ._psutil_windows import BELOW_NORMAL_PRIORITY_CLASS  # NOQA
     from ._psutil_windows import HIGH_PRIORITY_CLASS  # NOQA

psutil/_pswindows.py

@@ -12,7 +12,25 @@
 from collections import namedtuple
 
 from . import _common
-from . import _psutil_windows as cext
+try:
+    from . import _psutil_windows as cext
+except ImportError as err:
+    if str(err).lower().startswith("dll load failed") and \
+            sys.getwindowsversion()[0] < 6:
+        # We may get here if:
+        # 1) we are on an old Windows version
+        # 2) psutil was installed via pip + wheel
+        # See: https://github.com/giampaolo/psutil/issues/811
+        # It must be noted that psutil can still (kind of) work
+        # on outdated systems if compiled / installed from sources,
+        # but if we get here it means this this was a wheel (or exe).
+        msg = "this Windows version is too old (< Windows Vista); "
+        msg += "psutil 3.4.2 is the latest version which supports Windows "
+        msg += "2000, XP and 2003 server"
+        raise RuntimeError(msg)
+    else:
+        raise
+
 from ._common import conn_tmap
 from ._common import isfile_strict
 from ._common import parse_environ_block