Impact Acquire Python SDK DLL Load Failed

Symptoms

When using the Impact Acquire Python SDK, importing the Python module with a statement like:

from mvIMPACT import acquire

fails with an error message similar to:

ImportError: Failed to import test module: test_mvIMPACT_Acquire
Traceback (most recent call last):
  File "C:\Python311\Lib\unittest\loader.py", line 407, in _find_test_path
    module = self._get_module_from_name(name)
             ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Python311\Lib\unittest\loader.py", line 350, in _get_module_from_name
    __import__(name)
  File "C:\Users\user\my_python_app.py", line 13, in <module>
    from mvIMPACT import acquire
  File "C:\Python311\Lib\site-packages\mvimpact-2.50.0-py3.11-win-amd64.egg\mvIMPACT\__init__.py", line 1, in <module>
    from .acquire import *
  File "C:\Python311\Lib\site-packages\mvimpact-2.50.0-py3.11-win-amd64.egg\mvIMPACT\acquire.py", line 13, in <module>
    from . import lib_mvIMPACT_acquire
ImportError: DLL load failed while importing lib_mvIMPACT_acquire: The specified module could not be found.

Cause

This problem is caused by an unusual Impact Acquire installation path (or a missing installation). It should not occur if Impact Acquire is installed normally and the necessary libraries are installed to the %windir%/System32 directory. (or %windir%/SysWOW64 when running 32-bit applications on a 64-bit Windows system).

Resolution

By using os.add_dll_directory, it is possible to specify additional search paths for Python to use during DLL resolution. Adding the directory in which the libraries mvDeviceManager.dll, mvImageProcessing.dll, mvPropHandling.dll, etc. reside should be enough to resolve the issue.

Note that the call to os.add_dll_directory must occur before the Impact Acquire module is imported.