Thanks, I'll try these new steps and check what the default compiler is (according to meson). 

What should the name of the msvc compiler be (in meson)? I'm guessing it's not Clang, hah. Anyhow, I recall we can override this with environment variables if we need to. 

Thanks.

On Tue, Nov 11, 2025 at 8:13 PM Andre Muezerie <andremue@linux.microsoft.com> wrote:
On Mon, Nov 10, 2025 at 03:14:54PM -0800, Patrick Robb wrote:
> Hi Andre,
>
> At the DPDK Community Lab we are setting up a new windows build machine,
> which is a windows server 2025 VM. When this is ready we will retire our
> windows server 2022 VM which is running in CI currently.
>
> We also want to ensure that the new machine is picking up devx in the build
> per https://doc.dpdk.org/guides/platform/mlx5.html
>
> And we want to support the 3 compiler toolchains explained here:
> https://doc.dpdk.org/guides/windows_gsg/
>
> First, I'll note that we are able to build DPDK, including mlnx devx inc
> and lib successfully with Clang. So, that toolchain is all set.
>
> However, we also want to do a native build on Windows using MSVC. Per the
> instructions from the page above, we are following this procedure:
>
> 1. Open Powershell
> 2. Launch VsDevCmd.bat
> 3. meson setup with -Dstd_atomic=true
> 4. Build DPDK
>
> However, when I run meson setup, it indicates that Clang is the compiler.
> This is incorrect, right? Do I need to modify an env variable to set the
> compiler to MSVC? Here is the start of the meson setup if that helps
> clarify the situation:
>
> PS C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\Tools>
> ./VsDevCmd.bat -arch=amd64
> **********************************************************************
> ** Visual Studio 2022 Developer Command Prompt v17.14.17
> ** Copyright (c) 2025 Microsoft Corporation
> **********************************************************************
> PS C:\Program Files\Microsoft Visual Studio\2022\Community\Common7\Tools>
> cd /
> PS C:\> cd .\Users\
> PS C:\Users> cd .\Administrator\
> PS C:\Users\Administrator> cd .\Documents\
> PS C:\Users\Administrator\Documents> cd .\dpdk-new\
> PS C:\Users\Administrator\Documents\dpdk-new> meson setup
> -Denable_stdatomic=true build38
> The Meson build system
> Version: 1.9.1
> Source dir: C:\Users\Administrator\Documents\dpdk-new
> Build dir: C:\Users\Administrator\Documents\dpdk-new\build38
> Build type: native build
> Project name: DPDK
> Project version: 25.11.0-rc1
> C compiler for the host machine: clang (clang 17.0.1 "clang version 17.0.1")
> C linker for the host machine: clang link 14.44.35217.0
> Host machine cpu family: x86_64
>
>
>
> Do you see any errors in my setup? Thanks Andre.
>
> --
>
> Patrick Robb
>
> Open Source Labs Manager
>
> UNH Interoperability Labs
>
> 21 Madbury Rd, Suite 100, Durham, NH 03824
>
> www.iol.unh.edu


Hi Patrick,

I'm glad to hear that a Windows Server 2025 VM will be used to build DPDK using
the 3 compilers.

Good catch in finding that issue with the build. I never hit that because I always
use CMD instead of Powershell, but I see that the link mentioned in the
documentation might induce people to run the .bat script from PS. I'll fix that.

To get things working, this is my recommendation: just replace step (1) with:

1. Open cmd

Alternatively, if you really want to use Powershell you can call a PS flavor of
that script:

1. Open Powershell
2. & "C:\Program Files\Microsoft Visual Studio\2022\Enterprise\Common7\Tools\Launch-VsDevShell.ps1" -HostArch amd64 -Arch amd64

You might have to fix the location where the script is stored. It's stored in
the same location as VsDevCmd.bat.

After making this change please confirm the correct compiler is called, like you did before.

Thanks,

Andre Muezerie