On Fri, Nov 11, 2016 at 6:01 AM, Thorsten Kampe <thors...@thorstenkampe.de> wrote: > * eryk sun (Thu, 10 Nov 2016 23:04:02 +0000) >> >> On Thu, Nov 10, 2016 at 9:58 PM, Thorsten Kampe >> <thors...@thorstenkampe.de> wrote: >> > >> > I'm trying to run a script with a different Python version by >> > extending the path variable and executing "python.exe". It looks like >> > subprocess will always run the current executing Python. >> >> WinAPI CreateProcess checks the application directory, current >> directory (an insecure legacy default), %SystemRoot%\System32, >> %SystemRoot%\System, %SystemRoot%, and then the directories in %PATH%. >> This is listed in the documentation of the lpCommandLine parameter on >> MSDN [1]. > > I'm aware of that. Python is in F:\PortableApps\Python3x and neither > the current directory nor the PATH points to that.
That's the application directory, which is the first place CreateProcess looks (via the SearchPath call), as both of my examples shows. In my case python.exe is located in the standard 3.5 system installation path, "C:\Program Files\Python35". I showed how to remove the current directory from the search. But, in hindsight, I should have clarified that the working directory was not related to your problem. It's just the only directory that can be removed from the implicit search path (AFAIK). I thought about replying with a clarification, but it seemed clear in context that the source of the behavior was the application directory. I know of no API, environment variable, or manifest setting to remove the application directory from the head of the search path used by CreateProcess. What you can do is call SearchPath explicitly (via PyWin32 or ctypes) with just %Path%, or do the search in pure Python via shutil.which. Note also that LoadLibrary uses a separate DLL search path that also defaults to preferring the application directory, but this can be controlled by calling SetDefaultDllDirectories [1], among other strategies. [1]: https://msdn.microsoft.com/en-us/library/hh310515 -- https://mail.python.org/mailman/listinfo/python-list
