Merge pull request #87 from psyfood/dll

ENH, BF: Improved DLL search path configuration and switch back to using pywin32

.travis.yml

@@ -12,6 +12,12 @@ matrix:
     - os: linux
       env: PYTHON_VERSION=3.7
 
+    - os: linux
+      env: PYTHON_VERSION=3.8
+
+    - os: linux
+      env: PYTHON_VERSION=3.9
+
 before_install:
   - pwd
   - ./travis/00_install_miniconda.sh

CHANGES.md

@@ -1,5 +1,12 @@
+Version 2021.1
+--------------
+* Improve automated DLL search path configuration; the DLLs should be loadable
+  out-of-the-box in more situations now, including on systems running Python
+  3.8 and newer.
+* Switch back to using `pywin32` instead of `pypiwin32`.
+
 Version 2019.1
-------------------
+--------------
 * Handle non-existent configuration directory
 
 Version 2018.12.13

pyqmix/tools.py

@@ -88,16 +88,30 @@ def find_dll(dll_dir, dll_filename):
         dll_dir = appdirs.user_data_dir('QmixSDK', '')
         if os.path.exists(os.path.join(dll_dir, dll_filename)):
             dll_path = os.path.join(dll_dir, dll_filename)
-            # Add DLL dir to PATH, otherwise we won't be able to load the DLL.
-            os.environ['PATH'] += os.pathsep + dll_dir
+            # Add DLL dir to the DLL search path, otherwise we won't be able to
+            # load the DLL.
+            os.environ['PATH'] = dll_dir + os.pathsep + os.environ['PATH']
+            try:
+                # Python >= 3.8
+                os.add_dll_directory(dll_dir)
+            except NameError:
+                pass
+
             return dll_path
 
         return None
     else:
         if os.path.exists(os.path.join(dll_dir, dll_filename)):
             dll_path = os.path.join(dll_dir, dll_filename)
-            # Add DLL dir to PATH, otherwise we won't be able to load the DLL.
-            os.environ['PATH'] += os.pathsep + dll_dir
+            # Add DLL dir to the DLL search path, otherwise we won't be able to
+            # load the DLL.
+            os.environ['PATH'] = dll_dir + os.pathsep + os.environ['PATH']
+            try:
+                # Python >= 3.8
+                os.add_dll_directory(dll_dir)
+            except NameError:
+                pass
+
             return dll_path
         else:
             return None

requirements.txt

@@ -1,5 +1,5 @@
 cffi
 ruamel.yaml
 appdirs
-pypiwin32
+pywin32
 -e .

setup.cfg

@@ -22,13 +22,15 @@ classifiers =
     Programming Language :: Python :: 3
     Programming Language :: Python :: 3.6
     Programming Language :: Python :: 3.7
+    Programming Language :: Python :: 3.8
+    Programming Language :: Python :: 3.9
 
 [options]
 install_requires =
     cffi
-    ruamel.yaml
+    ruamel.yaml == 0.16.3
     appdirs
-    pypiwin32; platform_system == "Windows"
+    pywin32; platform_system == "Windows"
     future; python_version < '3'
 
 [bdist_wheel]