# How does CMAKE\_VS\_WINDOWS\_TARGET\_PLATFORM\_VERSION work?
**URL:** https://discourse.cmake.org/t/how-does-cmake-vs-windows-target-platform-version-work/260
**Category:** Code
**Created:** [November 26, 2019, 1:22pm UTC](https://discourse.cmake.org/t/how-does-cmake-vs-windows-target-platform-version-work/260 "2019-11-26T13:22:19Z")
**Posts on this page:** 5
**Page:** 1
### Author:  [@djspringate](https://discourse.cmake.org/u/djspringate)
#### Post date: [November 26, 2019, 1:22pm UTC](https://discourse.cmake.org/t/how-does-cmake-vs-windows-target-platform-version-work/260/1 "2019-11-26T13:22:19Z")
CMAKE\_VS\_WINDOWS\_TARGET\_PLATFORM\_VERSION
I’m running Windows 10 Home 1903 (OS Build 18362.46).
My C:\Program Files (x86)\Windows Kits\10\Lib folder contains:
10.0.16299.0
10.0.17134.0
10.0.17763.0
No matter what I do, CMAKE\_VS\_WINDOWS\_TARGET\_PLATFORM\_VERSION, returns 10.0.16299.0.
Surely, it should pick the highest version? What is the expected behaviour for this?
How is it supposed to work? This has been driving me nuts for a long time and only now have I realised I should be posting this here ^^
Thanks in advance for any help!
---
### Author:  [@robert.maynard](https://discourse.cmake.org/u/robert.maynard)
#### Post date: [November 26, 2019, 2:18pm UTC](https://discourse.cmake.org/t/how-does-cmake-vs-windows-target-platform-version-work/260/2 "2019-11-26T14:18:34Z")
This variable reports what Windows SDK is being targeted by the current build. Setting this variable has no effect, instead what you need to do is specify an explicit `CMAKE_SYSTEM_VERSION` when configuring a project for the first time.
I believe the reason that `10.0.16299.0` is being selected is that you might only have the runtime files for the other SDK’s and not the development headers.
---
### Author:  [@djspringate](https://discourse.cmake.org/u/djspringate)
#### Post date: [November 26, 2019, 5:14pm UTC](https://discourse.cmake.org/t/how-does-cmake-vs-windows-target-platform-version-work/260/3 "2019-11-26T17:14:48Z")
Hi Rob,
Thanks for the suggestions.
I checked and I have a whole bunch of headers under C:\Program Files (x86)\Windows Kits\10\Include\10.0.17763.0 etc.
What are valid settings for CMAKE\_SYSTEM\_VERSION?
Something like SET( CMAKE\_HOST\_SYSTEM\_VERSION 10.0.17763.0) ?
(I can’t check right now as I’m away from my dev PC)
---
### Author:  [@robert.maynard](https://discourse.cmake.org/u/robert.maynard)
#### Post date: [November 26, 2019, 6:00pm UTC](https://discourse.cmake.org/t/how-does-cmake-vs-windows-target-platform-version-work/260/4 "2019-11-26T18:00:05Z")
This isn’t my area of expertise but I believe it is specified via `CMAKE_SYSTEM_VERSION` and some logic internal to CMake.
@brad.king Is this correct?
---
### Author:  [@brad.king](https://discourse.cmake.org/u/brad.king)
#### Post date: [November 26, 2019, 6:12pm UTC](https://discourse.cmake.org/t/how-does-cmake-vs-windows-target-platform-version-work/260/5 "2019-11-26T18:12:06Z")
`CMAKE_HOST_SYSTEM_VERSION` is always computed automatically from the real host version.
A toolchain file can
```cmake
set(CMAKE_SYSTEM_VERSION 10.0)
```
The value `10.0` tells CMake to look for the largest available Windows SDK version. Or one can use any four-component version corresponding to a directory like `C:\Program Files (x86)\Windows Kits\10\Include\10.0.17763.0`, e.g.
```cmake
set(CMAKE_SYSTEM_VERSION 10.0.17763.0)
```
If building for a Windows target and the only thing you want to do is select the SDK version, you don’t need a toolchain file and can just define `CMAKE_SYSTEM_VERSION` on the command line, e.g.
```auto
cmake ../src -DCMAKE_SYSTEM_VERSION=10.0.17763.0
```