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pythonvisual-studio-2015static-librarieslibcmtd

I cannot build python.dll as a static library (/MTd) using Visual Studio

I am working with the 3.6.4 source release of Python. I have no trouble building it with Visual Studio as a dynamic library (/MDd) I can link the Python .dll to my own code and verify its operation.

But when I build it (and my code) with (/MTd) it soon runs off the rails when I try to open a file with a Python program. A Debug assertion fails in read.cpp ("Expression: _osfile(fh) & FOPEN"). What I believe is happening is the Python .dll is linking with improper system libraries. What I can't figure out is how to get it to link with the correct ones (static libraries).

Solution

  • This is what I needed to do to build and use python statically embedded in another application.

    To build the static python library (e.g., python36_d.lib, python36.lib)

    1. Convert ALL projects in the python solution (pcbuild.sln) to static. This is about 40 projects, so it may take awhile. This includes setting library products to be build as 'static lib', and setting all /MD and /MDd build options to /MT and /MTd.

    2. For at least the pythoncore project alter the Preprocess define to be Py_NO_ENABLE_SHARED. This tells the project it will be looking for calls from static libraries.

    3. By hook or crook, find yourself a pyconfig.h file and put it in the Include area of your Python build. It is unclear how this file is built from Windows tools, but one seems to be able to snag one from other sources and it works ok. One could probably grab the pyconfig.h from the Pre-compiled version of the code you are building. [By the way, the Python I built was 3.6.5 and was built with Windows 2015, update 3.]

    Hopefully, this should enable you to build both python36.lib and python36_d.lib. Now you need to make changes to your application project(s) to enable it to link with the python library. You need to do this:

    1. Add the Python Include directory to the General->Include Directories list.
    2. Add the Python Library directories to the General->Library Directories lists. This will be ..\PCBuild\win32 and ..\PCBuild\amd64.
    3. Add the define Py_NO_ENABLE_SHARED to the C/C++ -> Preprocessor area.
    4. For Linker->input add (for releases) python36.lib;shlwapi.lib;version.lib and (for debugs) python36_d.lib;shlwapi.lib;version.lib.

    And that should be it. It should run and work. But one more thing. In order to be able to function, the executable needs to access the Lib directory of the python build. So a copy of that needs to be moved to wherever the executable (containing the embedded python) resides. Or you can add the Lib area to the execution PATH for windows. That should work as well.

    That's about all of it.