Windows and Dynamic Loading of Extension Modules

If an application makes use of C/C++ extension modules that would normally be loaded dynamically by the Python interpreter library then you can often choose to build a static version of the extension module and link it directly with the deployed application. This reduces the number of files being deployed and avoids any possibility of conflicts with other versions of the same extension module installed on the target system.

However some extension modules are not able to be built statically and so a Python interpreter library that supports dynamic loading must be used. On Windows this is further complicated by the fact that the Python interpreter library can only support dynamic loading if it itself is built as a DLL. (On non-Windows platforms there is no problem in statically linking the Python interpreter library with the deployed application.)

Building the Python interpreter DLL on Windows is not particularly straightforward, especially if you want to customise it for your specific needs. It is strongly recommended that you always use a copy of the Python interpreter DLL (and associated extension modules) that is installed by the binary installer file from python.org. The install action of pyqtdeploycli will copy the required parts of a standard Python installation into the recommended directory structure described in Choosing a Directory Structure.