# How to force 64-bit build using Ninja on Windows?

**URL:** https://discourse.cmake.org/t/how-to-force-64-bit-build-using-ninja-on-windows/271
**Category:** Usage
**Created:** [November 27, 2019, 12:35pm UTC](https://discourse.cmake.org/t/how-to-force-64-bit-build-using-ninja-on-windows/271 "2019-11-27T12:35:58Z")
**Posts on this page:** 2
**Page:** 1

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### Author: ![DavidA](https://discourse.cmake.org/user_avatar/discourse.cmake.org/davida/32/128_2.png) [@DavidA](https://discourse.cmake.org/u/DavidA)
#### Post date: [November 27, 2019, 12:35pm UTC](https://discourse.cmake.org/t/how-to-force-64-bit-build-using-ninja-on-windows/271/1 "2019-11-27T12:35:58Z")

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I have two x64 Windows machines. One has Visual Studio Build Tools 2017 installed, the other has Visual Studio Build Tools 2019 installed.

On the machine with Visual Studio Build Tools 2019 I see:

```
>cmake -G Ninja ..
-- The CXX compiler identification is MSVC 19.23.28107.0
-- The C compiler identification is MSVC 19.23.28107.0
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.23.28105/bin/Hostx64/x64/cl.exe
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2019/BuildTools/VC/Tools/MSVC/14.23.28105/bin/Hostx64/x64/cl.exe -- works

```

i.e. x64 tools

On the machine with Visual Studio Build Tools 2017 I see:

```
>cmake -G Ninja ..
-- The CXX compiler identification is MSVC 19.16.27034.0
-- The C compiler identification is MSVC 19.16.27034.0
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x86/cl.exe
-- Check for working CXX compiler: C:/Program Files (x86)/Microsoft Visual Studio/2017/BuildTools/VC/Tools/MSVC/14.16.27023/bin/Hostx86/x86/cl.exe -- works

```

i.e. x86 tools

How can I force Ninja to use x64 tools on both platforms?

---

<div class="post-metadata">

### Author: ![DavidA](https://discourse.cmake.org/user_avatar/discourse.cmake.org/davida/32/128_2.png) [@DavidA](https://discourse.cmake.org/u/DavidA)
#### Post date: [November 27, 2019, 1:24pm UTC](https://discourse.cmake.org/t/how-to-force-64-bit-build-using-ninja-on-windows/271/2 "2019-11-27T13:24:37Z")

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The answer appears to be to call vcvars64.bat instead of VsDevCmd.bat. Perhaps I could have achieved the same result by passing a parameter to VsDevCmd.bat.