Re: [*SPAM*] Windows DPDK Build Help

[Andre Muezerie <andremue@linux.microsoft.com>]

On Wed, Nov 12, 2025 at 04:30:37PM -0500, Patrick Robb wrote:
> 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.
> 

Not Clang :-)
On my machine this is what shows up:

    C compiler for the host machine: cl (msvc 19.44.35220 "Microsoft (R) C/C++ Optimizing Compiler Version 19.44.35220 for x64")
    C linker for the host machine: link link 14.44.35220.0

You should get something similar to this.

> 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
> >