Hum, the change should be mentionned in Doc/whatsnew/3.7.rst.

AppVeyor compilation failed with: "C:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\shared\sdkddkver.h(289): fatal error C1189: #error: NTDDI_VERSION setting conflicts with _WIN32_WINNT setting [C:\projects\cpython\PCbuild\pythoncore.vcxproj]"

@vstinner There is some references to Vista in the Tools/msi/ directory.

@vstinner There is some references to Vista in the Tools/msi/ directory.

I don't know this directory, so I prefer to leave it unchanged.

@vstinner ok then in this case, the PR seems to be right.

AppVeyor compilation failed with: "C:\Program Files (x86)\Windows Kits\10\Include\10.0.16299.0\shared\sdkddkver.h(289): fatal error C1189: #error: NTDDI_VERSION setting conflicts with _WIN32_WINNT setting [C:\projects\cpython\PCbuild\pythoncore.vcxproj]"

@zooba: Do you understand why my change breaks the compilation?

"posixmodule.obj : error LNK2001: unresolved external symbol _GetMaximumProcessorCount [C:\projects\cpython\PCbuild\pythoncore.vcxproj]"

Oh, my posixmodule.c change doesn't work :-(

Extract of pythoninfo:

sys.windowsversion: sys.getwindowsversion(major=10, minor=0, build=14393, platform=2, service_pack='')
sys.winver: 3.7-32
sys.version: 3.7.0a4+ (heads/master-2-g1d7f51e:1d7f51e, Jan 18 2018, 05:42:21) [MSC v.1912 32 bit (Intel)]

I understand that AppVeyor runs Windows 10 and Python was built by Visual Studio 2017

https://msdn.microsoft.com/fr-fr/library/windows/desktop/dd405489(v=vs.85).aspx

"Remarks: To compile an application that uses this function, set _WIN32_WINNT >= 0x0601. For more information, see Using the Windows Headers."

Aha. I need to try to understand why changing _WIN32_WINNT failed. But my Windows VM is down :-)

Hum, I'm not sure that my PR is correct anymore. I change its status to WIP, I will rework on it, once I get again access to a Windows VM to fix my PR.