Download MSVC compiler/linker & Windows SDK without installing full Visual Studio

!README.md

This downloads standalone 64-bit MSVC compiler, linker & other tools, also headers/libraries from Windows SDK into portable folder, without installing Visual Studio. Has bare minimum components - no UWP/Store/WindowsRT stuff, just files & tools for 64-bit native desktop app development.

Run python.exe portable-msvc.py and it will download output into msvc folder. By default it will download latest available MSVC & Windows SDK - currently v14.32.17.2 and v10.0.22621.0.

You can list available versions with python.exe portable-msvc.py --show-versions and then pass versions you want with --msvc-version and --sdk-version arguments.

To use cl.exe/link.exe from output folder, first run setup.bat - after that PATH/INCLUDE/LIB env variables will be setup to use all the tools as usual. You can also use clang-cl.exe with these includes & libraries.

To use clang-cl.exe without running setup.bat, pass extra /winsysroot msvc argument (msvc is folder name where output is stored).

portable-msvc.py

#!/usr/bin/env python3

import io
import os
import sys
import json
import shutil
import hashlib
import zipfile
import tempfile
import argparse
import subprocess
import urllib.request
import urllib.error
from pathlib import Path

OUTPUT = Path("msvc") # output folder

# other architectures may work or may not - not really tested
HOST   = "x64" # or x86
TARGET = "x64" # or x86, arm, arm64

MANIFEST_URL = "https://aka.ms/vs/17/release/channel"
MANIFEST_PREVIEW_URL = "https://aka.ms/vs/17/pre/channel"

ssl_context = None

def download(url):
  with urllib.request.urlopen(url, context=ssl_context) as res:
    return res.read()

def download_progress(url, check, name, f):
  data = io.BytesIO()
  with urllib.request.urlopen(url, context=ssl_context) as res:
    total = int(res.headers["Content-Length"])
    size = 0
    while True:
      block = res.read(1<<20)
      if not block:
        break
      f.write(block)
      data.write(block)
      size += len(block)
      perc = size * 100 // total
      print(f"\r{name} ... {perc}%", end="")
  print()
  data = data.getvalue()
  digest = hashlib.sha256(data).hexdigest()
  if check.lower() != digest:
    exit(f"Hash mismatch for f{pkg}")
  return data

# super crappy msi format parser just to find required .cab files
def get_msi_cabs(msi):
  index = 0
  while True:
    index = msi.find(b".cab", index+4)
    if index < 0:
      return
    yield msi[index-32:index+4].decode("ascii")

def first(items, cond):
  return next(item for item in items if cond(item))
  

### parse command-line arguments

ap = argparse.ArgumentParser()
ap.add_argument("--show-versions", action="store_true", help="Show available MSVC and Windows SDK versions")
ap.add_argument("--accept-license", action="store_true", help="Automatically accept license")
ap.add_argument("--msvc-version", help="Get specific MSVC version")
ap.add_argument("--sdk-version", help="Get specific Windows SDK version")
ap.add_argument("--preview", action="store_true", help="Use preview channel for Preview versions")

args = ap.parse_args()
print(args.preview)


### get main manifest

URL = MANIFEST_PREVIEW_URL if args.preview else MANIFEST_URL

try:
  manifest = json.loads(download(URL))
except urllib.error.URLError as err:
  import ssl
  if isinstance(err.args[0], ssl.SSLCertVerificationError):
    # for more info about Python & issues with Windows certificates see https://stackoverflow.com/a/52074591
    print("ERROR: ssl certificate verification error")
    try:
      import certifi
    except ModuleNotFoundError:
      print("ERROR: please install 'certifi' package to use Mozilla certificates")
      print("ERROR: or update your Windows certs, see instructions here: https://woshub.com/updating-trusted-root-certificates-in-windows-10/#h2_3")
      exit()
    print("NOTE: retrying with certifi certificates")
    ssl_context = ssl.create_default_context(cafile=certifi.where())
    manifest = json.loads(download(URL))
  else:
    raise

### download VS manifest

ITEM_NAME = "Microsoft.VisualStudio.Manifests.VisualStudioPreview" if args.preview else "Microsoft.VisualStudio.Manifests.VisualStudio"

vs = first(manifest["channelItems"], lambda x: x["id"] == ITEM_NAME)
payload = vs["payloads"][0]["url"]

vsmanifest = json.loads(download(payload))


### find MSVC & WinSDK versions

packages = {}
for p in vsmanifest["packages"]:
  packages.setdefault(p["id"].lower(), []).append(p)

msvc = {}
sdk = {}

for pid,p in packages.items():
  if pid.startswith("Microsoft.VisualStudio.Component.VC.".lower()) and pid.endswith(".x86.x64".lower()):
    pver = ".".join(pid.split(".")[4:6])
    if pver[0].isnumeric():
      msvc[pver] = pid
  elif pid.startswith("Microsoft.VisualStudio.Component.Windows10SDK.".lower()) or \
       pid.startswith("Microsoft.VisualStudio.Component.Windows11SDK.".lower()):
    pver = pid.split(".")[-1]
    if pver.isnumeric():
      sdk[pver] = pid

if args.show_versions:
  print("MSVC versions:", " ".join(sorted(msvc.keys())))
  print("Windows SDK versions:", " ".join(sorted(sdk.keys())))
  exit(0)

msvc_ver = args.msvc_version or max(sorted(msvc.keys()))
sdk_ver = args.sdk_version or max(sorted(sdk.keys()))

if msvc_ver in msvc:
  msvc_pid = msvc[msvc_ver]
  msvc_ver = ".".join(msvc_pid.split(".")[4:-2])
else:
  exit(f"Unknown MSVC version: f{args.msvc_version}")

if sdk_ver in sdk:
  sdk_pid = sdk[sdk_ver]
else:
  exit(f"Unknown Windows SDK version: f{args.sdk_version}")

print(f"Downloading MSVC v{msvc_ver} and Windows SDK v{sdk_ver}")


### agree to license

tools = first(manifest["channelItems"], lambda x: x["id"] == "Microsoft.VisualStudio.Product.BuildTools")
resource = first(tools["localizedResources"], lambda x: x["language"] == "en-us")
license = resource["license"]

if not args.accept_license:
  accept = input(f"Do you accept Visual Studio license at {license} [Y/N] ? ")
  if not accept or accept[0].lower() != "y":
    exit(0)

OUTPUT.mkdir(exist_ok=True)
total_download = 0

### download MSVC

msvc_packages = [
  # MSVC binaries
  f"microsoft.vc.{msvc_ver}.tools.host{HOST}.target{TARGET}.base",
  f"microsoft.vc.{msvc_ver}.tools.host{HOST}.target{TARGET}.res.base",
  # MSVC headers
  f"microsoft.vc.{msvc_ver}.crt.headers.base",
  # MSVC libs
  f"microsoft.vc.{msvc_ver}.crt.{TARGET}.desktop.base",
  f"microsoft.vc.{msvc_ver}.crt.{TARGET}.store.base",
  # MSVC runtime source
  f"microsoft.vc.{msvc_ver}.crt.source.base",
  # ASAN
  f"microsoft.vc.{msvc_ver}.asan.headers.base",
  f"microsoft.vc.{msvc_ver}.asan.{TARGET}.base",
  # MSVC redist
  #f"microsoft.vc.{msvc_ver}.crt.redist.x64.base",
]

for pkg in msvc_packages:
  p = first(packages[pkg], lambda p: p.get("language") in (None, "en-US"))
  for payload in p["payloads"]:
    with tempfile.TemporaryFile() as f:
      data = download_progress(payload["url"], payload["sha256"], pkg, f)
      total_download += len(data)
      with zipfile.ZipFile(f) as z:
        for name in z.namelist():
          if name.startswith("Contents/"):
            out = OUTPUT / Path(name).relative_to("Contents")
            out.parent.mkdir(parents=True, exist_ok=True)
            out.write_bytes(z.read(name))


### download Windows SDK

sdk_packages = [
  # Windows SDK tools (like rc.exe & mt.exe)
  f"Windows SDK for Windows Store Apps Tools-x86_en-us.msi",
  # Windows SDK headers
  f"Windows SDK for Windows Store Apps Headers-x86_en-us.msi",
  f"Windows SDK Desktop Headers x86-x86_en-us.msi",
  # Windows SDK libs
  f"Windows SDK for Windows Store Apps Libs-x86_en-us.msi",
  f"Windows SDK Desktop Libs {TARGET}-x86_en-us.msi",
  # CRT headers & libs
  f"Universal CRT Headers Libraries and Sources-x86_en-us.msi",
  # CRT redist
  #"Universal CRT Redistributable-x86_en-us.msi",
]

with tempfile.TemporaryDirectory() as d:
  dst = Path(d)

  sdk_pkg = packages[sdk_pid][0]
  sdk_pkg = packages[first(sdk_pkg["dependencies"], lambda x: True).lower()][0]

  msi = []
  cabs = []

  # download msi files
  for pkg in sdk_packages:
    payload = first(sdk_pkg["payloads"], lambda p: p["fileName"] == f"Installers\\{pkg}")
    msi.append(dst / pkg)
    with open(dst / pkg, "wb") as f:
      data = download_progress(payload["url"], payload["sha256"], pkg, f)
      total_download += len(data)
      cabs += list(get_msi_cabs(data))

  # download .cab files
  for pkg in cabs:
    payload = first(sdk_pkg["payloads"], lambda p: p["fileName"] == f"Installers\\{pkg}")
    with open(dst / pkg, "wb") as f:
      data = download_progress(payload["url"], payload["sha256"], pkg, f)
      total_download += len(data)

  print("Unpacking msi files...")

  # run msi installers
  for m in msi:
    subprocess.check_call(["msiexec.exe", "/a", m, "/quiet", "/qn", f"TARGETDIR={OUTPUT.resolve()}"])


### versions

msvcv = list((OUTPUT / "VC/Tools/MSVC").glob("*"))[0].name
sdkv = list((OUTPUT / "Windows Kits/10/bin").glob("*"))[0].name


# place debug CRT runtime files into MSVC folder (not what real Visual Studio installer does... but is reasonable)

dst = OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{HOST}/{TARGET}"

with tempfile.TemporaryDirectory() as d:
  d = Path(d)
  pkg = "microsoft.visualcpp.runtimedebug.14"
  dbg = first(packages[pkg], lambda p: p["chip"] == HOST)
  for payload in dbg["payloads"]:
    name = payload["fileName"]
    with open(d / name, "wb") as f:
      data = download_progress(payload["url"], payload["sha256"], f"{pkg}/{name}", f)
      total_download += len(data)
  msi = d / first(dbg["payloads"], lambda p: p["fileName"].endswith(".msi"))["fileName"]

  with tempfile.TemporaryDirectory() as d2:
    subprocess.check_call(["msiexec.exe", "/a", str(msi), "/quiet", "/qn", f"TARGETDIR={d2}"])
    for f in first(Path(d2).glob("System*"), lambda x: True).iterdir():
      f.replace(dst / f.name)

# download DIA SDK and put msdia140.dll file into MSVC folder

with tempfile.TemporaryDirectory() as d:
  d = Path(d)
  pkg = "microsoft.visualc.140.dia.sdk.msi"
  dia = packages[pkg][0]
  for payload in dia["payloads"]:
    name = payload["fileName"]
    with open(d / name, "wb") as f:
      data = download_progress(payload["url"], payload["sha256"], f"{pkg}/{name}", f)
      total_download += len(data)
  msi = d / first(dia["payloads"], lambda p: p["fileName"].endswith(".msi"))["fileName"]

  with tempfile.TemporaryDirectory() as d2:
    subprocess.check_call(["msiexec.exe", "/a", str(msi), "/quiet", "/qn", f"TARGETDIR={d2}"])

    if HOST == "x86": msdia = "msdia140.dll"
    elif HOST == "x64": msdia = "amd64/msdia140.dll"
    else: exit("unknown")

    src = Path(d2) / "Program Files" / "Microsoft Visual Studio 14.0" / "DIA SDK" / "bin" / msdia
    src.replace(dst / "msdia140.dll")


### cleanup

shutil.rmtree(OUTPUT / "Common7", ignore_errors=True)
for f in ["Auxiliary", f"lib/{TARGET}/store", f"lib/{TARGET}/uwp"]:
  shutil.rmtree(OUTPUT / "VC/Tools/MSVC" / msvcv / f)
for f in OUTPUT.glob("*.msi"):
  f.unlink()
for f in ["Catalogs", "DesignTime", f"bin/{sdkv}/chpe", f"Lib/{sdkv}/ucrt_enclave"]:
  shutil.rmtree(OUTPUT / "Windows Kits/10" / f, ignore_errors=True)
for arch in ["x86", "x64", "arm", "arm64"]:
  if arch != TARGET:
    shutil.rmtree(OUTPUT / "Windows Kits/10/Lib" / sdkv / "ucrt" / arch)
    shutil.rmtree(OUTPUT / "Windows Kits/10/Lib" / sdkv / "um" / arch)
  if arch != HOST:
    shutil.rmtree(OUTPUT / "Windows Kits/10/bin" / sdkv / arch)
# executable that is collecting & sending telemetry every time cl/link runs
(OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{HOST}/{TARGET}/vctip.exe").unlink(missing_ok=True)


### setup.bat

SETUP = f"""@echo off

set ROOT=%~dp0

set MSVC_VERSION={msvcv}
set MSVC_HOST=Host{HOST}
set MSVC_ARCH={TARGET}
set SDK_VERSION={sdkv}
set SDK_ARCH={TARGET}

set MSVC_ROOT=%ROOT%VC\\Tools\\MSVC\\%MSVC_VERSION%
set SDK_INCLUDE=%ROOT%Windows Kits\\10\\Include\\%SDK_VERSION%
set SDK_LIBS=%ROOT%Windows Kits\\10\\Lib\\%SDK_VERSION%

set VCToolsInstallDir=%MSVC_ROOT%\\
set PATH=%MSVC_ROOT%\\bin\\%MSVC_HOST%\\%MSVC_ARCH%;%ROOT%Windows Kits\\10\\bin\\%SDK_VERSION%\\%SDK_ARCH%;%ROOT%Windows Kits\\10\\bin\\%SDK_VERSION%\\%SDK_ARCH%\\ucrt;%PATH%
set INCLUDE=%MSVC_ROOT%\\include;%SDK_INCLUDE%\\ucrt;%SDK_INCLUDE%\\shared;%SDK_INCLUDE%\\um;%SDK_INCLUDE%\\winrt;%SDK_INCLUDE%\\cppwinrt
set LIB=%MSVC_ROOT%\\lib\\%MSVC_ARCH%;%SDK_LIBS%\\ucrt\\%SDK_ARCH%;%SDK_LIBS%\\um\\%SDK_ARCH%
"""

(OUTPUT / "setup.bat").write_text(SETUP)

print(f"Total downloaded: {total_download>>20} MB")
print("Done!")

Right, this downloads MSVC compiler & linker and Windows SDK headers & libs. Not clang. You can install clang from their github releases. It will be able to use Windows headers & libs from this script.

Perfect, thank you!

Leaving this here for future masochists to find on Google:

Want to use .NET NativeAOT with this script's Visual Studio environment? Pass in /p:IlcUseEnvironmentalTools=true into dotnet publish.

Hope this helps! I sure wish someone had documented this before... but oh well, atleast others won't suffer as much as I did

I hit this error, what cert does it complain about?

    return self.do_open(http.client.HTTPSConnection, req,
           ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "C:\Users\user\AppData\Local\Programs\Python\Python312\Lib\urllib\request.py", line 1347, in do_open
    raise URLError(err)
urllib.error.URLError: <urlopen error [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1000)>

Script is connecting to Microsoft server to download MSVC. Expired certificate may be result of incorrect date on your computer - check that you have correct date set. Another reason could be bad 3rd party proxy / firewall / network monitoring or security software which is intercepting all https requests.

@mmozeiko great advice!
so I opened up the certmgr.msc util and went one by one over all the cert hives and just deleted those that are older then 2024!
it did the trick and I was able to successfully run the script!

proofs -

c:\Prg\>python portable-msvc.py --show-versions
MSVC versions: 14.29 14.30 14.31 14.32 14.33 14.34 14.35 14.36 14.37 14.38 14.39
Windows SDK versions: 18362 19041 20348 22000 22621

btw, what is the goal of adding this into latest script?

  # executable that is collecting & sending telemetry every time cl/link runs
  (OUTPUT / "VC/Tools/MSVC" / msvcv / f"bin/Host{arch}/{arch}/vctip.exe").unlink(missing_ok=True)

It deletes vctip.exe ("VC++ Technology Improvement Program") which is runs every time you run cl/link and sends telemetry to Microsoft servers. Compiler & linker still works fine without this file. I don't want compiler making network requests every time I compile something.

You can also opt out of MSVC telemetry by editing registry: https://learn.microsoft.com/en-us/visualstudio/ide/visual-studio-experience-improvement-program#registry-settings But it requires changing HKLM keys, so admin rights required, which I don't want for this python script.

To resolve the SSL error ssl.SSLCertVerificationError: [SSL: CERTIFICATE_VERIFY_FAILED] certificate verify failed: certificate has expired (_ssl.c:1000)
You can add these two lines at the beginning of the portable-msvc.py.

import ssl
ssl._create_default_https_context = ssl._create_unverified_context

That is a bad way to solve this problem. Do not ever do that. It disables TLS verification, so you won't know if things you connect & download are valid and not intercepted/mangled with. Fix your computer time & apply OS updates instead.

hi! it seems it's not possible to download hostx64-86 cross toolchain? the bin directory barely have any files afterward.
I tried another tool and the result was the sazme.
it seems this is an issue on microsoft's side?

also, running the script with python 3.12 results in NameError: name 'exit' is not defined
the solution seems to be replacing exit(0) with sys.exit(0).

feature request: is it possible to add the ability to specify the folder where the toolchain is located? at the moment it seems to be hardcoded to msvc.

There's no issue on MS side. I just never really tested other hosts/targets than x64. I've fixed the script so it now works for x64 host & x86 target. arm/arm64 may still be not properly done, have not tested it.

Not sure why you see error with exit - it is perfectly valid to call, even in Python 3.12: https://docs.python.org/3/library/constants.html#exit
Only issue I could see is that your Python installation is done in a strange way that does not have default site module.

You can just rename msvc folder after script runs. It's not like this code keeps track of this folder and keeps it up to date or tracks what is installed. This tool is not supposed to be fancy installer. Just a quick "run once and forget" kind of tool.

Hi @florianingerl How did you solved the issue? Installing in C: Directory also give the same error.

Hi all. I would like to use the portable version of MSVC with VSCode and the associated Microsoft plugins (C/C++ and CMake-tools). Unfortunately, as expected, these tools rely, not on the simple env variables used, but on the official over-complicated mechanism for detecting the installation of MSVC (.bat of the MSVC console and also probably vswhere.exe and registry keys).
Does anyone know how to do the equivalent setup manually? I've tried many things by picking up technical elements from cmake, ninja, etc... but I haven't found any functional solution. If anyone knows how to do it, it would be great. Thanks

I don't know VScode, but cmake will find all the compiler executable from PATH - so as long as you run setup.bat it will just work. If you don't want to run setup.bat, you can manually specify cl.exe, link, lib.exe, etc.. locations with cmake variables.

I believe you'll need at least these:

• CMAKE_C_COMPILER=path/to/cl.exe
• CMAKE_CXX_COMPILER=path/to/cl.exe
• CMAKE_C_COMPILER_LINKER=path/to/link.exe
• CMAKE_CXX_COMPILER_LINKER=path/to/link.exe
• CMAKE_AR_COMPILER=path/to/lib.exe
• CMAKE_MT_COMPILER=path/to/mt.exe

Instead of manually specifying these variables every time, you can create cmake toolchain file and the pass it with -DCMAKE_TOOLCHAIN_FILE argument, see the docs here: https://cmake.org/cmake/help/latest/manual/cmake-toolchains.7.html

But again - easiest way is just to run setup.bat and then cmake -G Ninja path/to/project will just work. No need for vswhere or registry keys.

Any Linux equivalent available? It tries to run msiexec.exe.
I get

...
f9ff50431335056fb4fbac05b8268204.cab ... 100%
Unpacking msi files...
Traceback (most recent call last):
  File "/home/ephemssss/novorender/ifc2brep-0/scripts/external-tools/portable-msvc.py", line 248, in <module>
    subprocess.check_call(["msiexec.exe", "/a", m, "/quiet", "/qn", f"TARGETDIR={OUTPUT.resolve()}"])
  File "/usr/lib/python3.10/subprocess.py", line 364, in check_call
    retcode = call(*popenargs, **kwargs)
  File "/usr/lib/python3.10/subprocess.py", line 345, in call
    with Popen(*popenargs, **kwargs) as p:
  File "/usr/lib/python3.10/subprocess.py", line 971, in __init__
    self._execute_child(args, executable, preexec_fn, close_fds,
  File "/usr/lib/python3.10/subprocess.py", line 1863, in _execute_child
    raise child_exception_type(errno_num, err_msg, err_filename)
FileNotFoundError: [Errno 2] No such file or directory: 'msiexec.exe'

It seems there exists msiextract tool, I have not tried using it myself: https://manpages.ubuntu.com/manpages/focal/man1/msiextract.1.html

.. but on the official over-complicated mechanism for detecting the installation of MSVC (.bat of the MSVC console and also probably vswhere.exe and registry keys). Does anyone know how to do the equivalent setup manually?

@lolo120916 For vswhere detection see my finding above, it's possible but kinda complicated. At least it works with Flutter last time I tried.

I used procmon to detect how the registry/vswhere works, but probably still missed some things.

@mmozeiko and @AndhikaWB
Thank you both. What I did was restart from scratch with VS Code. I did the simplest thing possible, as suggested by mmozeiko (by the way, huge thanks for his script and for taking the time to respond to messages), I launched VS Code with the environment variables set by setup.bat. And then, in VS Code, I simply added "cmake.generator": "Ninja" to the project's settings.json (and nothing more, especially). I then generated the CMakeLists.txt using the `"CMake: Quick Start" command. With the "CMake Tools" extension, I was then able to build and debug the project step by step.
Phew. Ninja handles everything on its own: it's wonderful.
Above all, don't try to do anything more complicated as suggested in the docs of the C/C++ and CMake Tools extensions: without MSVC console and without vswhere.exe able to detect things automagically, it just creates chaos ;-).