Trouble building pywin32 with Visual Studio 2005

[kyosohma at gmail.com]

On Nov 14, 12:41 pm, danf... at gmail.com wrote:
> Hi everybody...
>
> I'm hoping one of you reading this can help me out here. I'm having
> trouble getting pywin32 to build with Visual Studio 2005. But first,
> some background.
>
> I'm embedding Python in an MFC application. I've manually built
> Python .lib and .dll files using Visual Studio 2005 from the solution/
> project files in the PCBuild8 folder. I've got a totally happy,
> working Python interpreter in my MFC application.
>
> When I use pre-built pywin32 packages, some strange crashes occur.
> Specifically, if I import win32com.server.register and call the
> RegisterClasses function, I get a complaint regarding an attempt to
> free unallocated memory.
>
> Now, my theory on this issue is that DLLs like win32api.pyd, which I
> acquired pre-built, were built with Visual Studio 2003, and they
> depend on msvcr71.dll. My Python/MFC application, on the other hand,
> was built with Visual Studio 2005, and is linking with msvcr80.dll. If
> memory gets allocated through one DLL, and an attempt is made at
> freeing it in the other DLL, bad things can happen, since the freeing
> DLL doesn't have any header information on the allocated memory.
>
> In order to test this theory (and potentially fix it), I want to re-
> build the pywin32 stuff using Visual Studio 2005. Now I've never built
> pywin32, so please excuse any "noobness" from here on out. I
> downloaded the pywin32-210.zip source from sourceforge. I tried
> running "setup.py build" per the Readme, and I received the following
> message.
>
> Warning - can't find an installed platform SDK
> error: Python was built with Visual Studio 2003;
> extensions must be built with a compiler that can generate compatible
> binaries. Visual Studio 2003 was not found on this system. if you have
> Cygwin installed, you can try compiling with MingW32, by passing "-c
> mingw32" to setup.py.
>
> (Note that I don't have the Platform SDK - This is a Vista machine, so
> I've got what they now are calling the Windows SDK. If it ends up
> being a problem, I'll tackle it when it shows up)
>
> The logical conclusion to jump to from this error message is that
> pywin32 is trying to build with VS2005, but it thinks that Python was
> built with VS2003. Well, in a manner of speaking, that is true. I did
> have a regular Python installation in C:\Python25, straight from one
> of the MSI installers. That regular Python installation was
> undoubtedly compiled with VS2003. I guess what I need to do is find a
> way to replace the default installation, or certain files within it,
> with stuff I compiled myself using VS2005. I tried replacing all of
> the python25[_d].dll and python[w][_d].exe files with those that I
> built, and that isn't helping. I considered creating a Python
> installer with the msi.py that is included in the Python Source, but
> that requires pywin32 (according to the README), and that's what I'm
> trying to build.
>
> I tried going through the setup.py code to find out where it is
> acquiring this "Python was built with Visual Studio 2003" information,
> but I keep getting lost in the code, so I can't figure out which, if
> any, file(s) to change/replace.

Probably the easiest way to "fix" this is to use MinGW or VS2003 or
recompile your MFC using MingW against what amounts to VS2003. I've
heard from multiple sources that trying to compile "impure" Python
extensions against anything other than the original compiler can (and
does) lead to screwy issues.

Of course, there is the theory that you could compile your own Python
using VS2005 and then it should "just work"...but from what I've
heard, even the Python developers are skipping VS2005 and heading
straight to VS2008.

Not very helpful, I know. You may get better help from the people on
the PyWin32 user's group. See http://mail.python.org/mailman/listinfo/python-win32

Mike