为什么python27.dll不是python安装文件夹的一部分，而是在Windows系统文件夹中

Question

As described in: http://bugs.python.org/issue22139 , the python27.dll is installed in the windows systems (in my case C:\\Windows\\Systems32) folder.

But I would like to know why? Why is it not installed next to the python.exe, for example in C:\\Python27\\?

Reason I ask: I've made a mercurial hook in python that our developers need to use to check if the commit message is valid. It checks ao for a valid JIRA issue number. To prevent all our developers to install python themselves and install the required modules manually (a lot of work and errorprone), I zipped the python installation and asked the developers to unzip it locally. But they can't run it, because the python27.dll is missing, or worse, they already have another minor version of python installed, and the hook will fail due to the wrong python27.dll used. Confusing. If I just add the python27.dll (the correct version) to the zip file, it all seems to work great. So, why is it not installed in that location in the first place? What is the advantage of installing it in C:\\Windows\\System32?

Hope someone can explain this to me! Thanks in advance, Tallandtree.

Answer 1

I use the Anaconda Python distribution from http://continuum.io . They put python27.dll into c:\\anaconda right next to its python.exe. This distribution is also superior in that you can have multiple python environments with precisely the packages you need and switch between them easily ( http://conda.pydata.org/docs/using/envs.html ). You can also get the package list of one of your environments and distribute it to others.

I recommend this Python distribution over the one from python.org and Enthought, because of this issue.

Answer 2

.dll s are quite windows-specific files. I imagine you will have shared object (.so) files for LINUX/UNIX-specific Python stuff? You said your developer's couldn't run it, because they didn't have the correct DLL (ie the one relevant to their Python installation).

Also, the advantage of installing it to System32 is that it's in the default PATH. Additionally, if any other application is internally using Python and require access to the .dll file, and also NOT reference your Python directory, they will probably be looking for a location that "Actually" exists (I wanted to say guaranteed to exist, but......never mind). That location would be `C:/windows/Systems32'.

Answer 3

I found it to work just fine to put python27.dll in the Python directory (c:\\Python27 or wherever). As long as it's in the PATH, it seems to work. I did this for a "relocatable" installation of Python. I can copy the installation directory to a Windows machine that has no Python installed, set the PATH to include that directory, and run Python, including all the libraries I had installed with pip install on the original machine.