CMake -G Ninja on Windows specify x64

Question

I am using CMake on Windows with Ninja generator

cmake -G Ninja ..

This uses the default Windows x86 toolchain. How to specify x64 using the Ninja generator?

PS: I know how to generate x64 with Visual Studio

cmake -G "Visual Studio 12 2013 Win64 ..

Terrell

Answer 1

You have to set the compiler environment accordingly before calling Ninja generation. If you have Visual Studio 2013 installed at the standard installation path you call:

"C:\Program Files (x86)\Microsoft Visual Studio 12.0\VC\vcvarsall.bat" x64
cmake.exe -G "Ninja" ..

---

Edit: Thanks for the hint from @Antwane: "Or simply run CMake command from a Microsoft Visual Studio Command Prompt (x64). A shortcut to this prompt is located in Start Menu".

The naming varies over the Visual Studio versions:

---

When I then look into the generated CMakeCache.txt file I see:

...
//CXX compiler
CMAKE_CXX_COMPILER:FILEPATH=C:/Program Files (x86)/Microsoft Visual Studio 12.0/VC/bin/amd64/cl.exe
...
//Flags used by the linker.
CMAKE_EXE_LINKER_FLAGS:STRING= /machine:x64
...
//Path to a program.
CMAKE_LINKER:FILEPATH=C:/Program Files (x86)/Microsoft Visual Studio 12.0/VC/bin/amd64/link.exe
...

Ferreira

Or simply run CMake command from a "Microsoft Visual Stduio Command Prompt (x64)". A shortcut to this prompt is located in Start Menu – Atlanta

Note that /DWIN32 is still set in the Cache file. This comes from Windows-MSVC.cmake – Rotifer

Is there a way in powershell to do this ? – Monahan

@GengJiawen I used the function from this answer to call vcvarsall.bat inside powershell and set up the environment properly. – Dipper

after vcvarsall.bat x64 you can add a & and then the rest of the cmake command line (I saw that used here) which makes this scriptable – Arni

Answer 2

When I tried to run cmake on command line in Windows, trying to use Ninja and targetting the Visual Studio 14.0 compiler (2015), it kept picking up on other installed compilers (in my case gcc) instead.

The following command line worked:

cmake -G Ninja -DCMAKE_BUILD_TYPE=Debug -DCMAKE_C_COMPILER="cl.exe" -DCMAKE_CXX_COMPILER="cl.exe" -DMSVC_TOOLSET_VERSION=140 ..

Homeomorphism

In my machine this gavem cl.exe is not a full path and was not found in the PATH. Guess need to give full paths then – Intercept

Answer 3

This answer assumes you have Visual Studio installed and have installed all the proper C++ libraries and what not when you installed visual studio.

Start typing in "x64 Native Tools" in your start menu. Open the file location and you will see a certain amount of shortcuts. On my visual studio installation I only have compilers for the x86/x64 architecture.

Anyway now that you have opened the file location you will be presented with a bunch of developer command prompt shortcuts:

PS C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Visual Studio 2019\Visual Studio Tools\VC> ls

    Directory: C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Visual Studio 2019\Visual Studio Tools\VC

Mode                 LastWriteTime         Length Name
----                 -------------         ------ ----
-a---           2/16/2021  8:12 PM           2139 x64 Native Tools Command Prompt for VS 2019 Preview.lnk
-a---           2/16/2021  8:12 PM           2197 x64_x86 Cross Tools Command Prompt for VS 2019 Preview.lnk
-a---            3/3/2021  9:01 PM           2139 x86 Native Tools Command Prompt for VS 2019 Preview.lnk
-a---           2/16/2021  8:12 PM           2197 x86_x64 Cross Tools Command Prompt for VS 2019 Preview.lnk

PS C:\ProgramData\Microsoft\Windows\Start Menu\Programs\Visual Studio 2019\Visual Studio Tools\VC>

Let me explain what each one does:

• x64 Native Tools Command Prompt for VS 2019 Preview

  • Use x64 compiler to compile for a x64 machine

• x64_x86 Cross Tools Command Prompt for VS 2019 Preview

  • Use x64 compiler to compile for a x86 machine

• x86 Native Tools Command Prompt for VS 2019 Preview

  • Use x86 compiler to compile for a x86 machine

• x86_x64 Cross Tools Command Prompt for VS 2019 Preview

  • Use x86 compiler to compile for a x64 machine

In my opinion the last 2 are useless in the modern day. And have caused multiple CI crashes on our servers. So we only use 64 bit binaries.

Anyway you double click on one of the shortcuts:

**********************************************************************
** Visual Studio 2019 Developer Command Prompt v16.10.0-pre.1.0
** Copyright (c) 2021 Microsoft Corporation
**********************************************************************
[vcvarsall.bat] Environment initialized for: 'x64'

C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview>

And bang you will have a command prompt loaded with an environment CMake can recognize. This is because the PATH environment variable now contains the compilers and what not.

C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview>echo %PATH%
C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\\Extensions\Microsoft\IntelliCode\CLI;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\VC\Tools\MSVC\14.29.29917\bin\HostX64\x64;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\VC\VCPackages;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\CommonExtensions\Microsoft\TestWindow;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\CommonExtensions\Microsoft\TeamFoundation\Team Explorer;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\MSBuild\Current\bin\Roslyn;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Team Tools\Performance Tools\x64;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Team Tools\Performance Tools;C:\Program Files (x86)\Microsoft Visual Studio\Shared\Common\VSPerfCollectionTools\vs2019\\x64;C:\Program Files (x86)\Microsoft Visual Studio\Shared\Common\VSPerfCollectionTools\vs2019\;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\Tools\devinit;C:\Program Files (x86)\Windows Kits\10\bin\10.0.19041.0\x64;C:\Program Files (x86)\Windows Kits\10\bin\x64;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\\MSBuild\Current\Bin;C:\Windows\Microsoft.NET\Framework64\v4.0.30319;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\Tools\;C:\WINDOWS\system32;C:\WINDOWS;C:\WINDOWS\System32\Wbem;C:\WINDOWS\System32\WindowsPowerShell\v1.0\;C:\WINDOWS\System32\OpenSSH\;C:\Program Files\LLVM\bin;C:\Program Files\Git\cmd;C:\Program Files\PowerShell\7\;C:\Program Files\CMake\bin;D:\Installations\Python\Scripts\;D:\Installations\Python\;C:\Users\juanr\AppData\Local\Microsoft\WindowsApps;D:\Installations\Microsoft VS Code\bin;C:\Users\juanr\AppData\Local\GitHubDesktop\bin;D:\Git\ninja;;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\VC\Tools\Llvm\x64\bin;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\CommonExtensions\Microsoft\CMake\CMake\bin;C:\Program Files (x86)\Microsoft Visual Studio\2019\Preview\Common7\IDE\CommonExtensions\Microsoft\CMake\Ninja

Now you can run cmake with Ninja:

NOTE: In this example I'm manually specifying the path to Ninja. You can also just add Ninja to your path. And depending on your visual studio installation this may already be done for you. If you download the "C++ CMake tools for Windows" you have Ninja added to your path for you. You even get CMake added for you.

cmake -S . -B build -G "Ninja" -DCMAKE_MAKE_PROGRAM=C:/foobar/ninja.exe

Gains