msvcup

# msvcup

A standalone tool for installing the MSVC toolchain and Windows SDK without Visual Studio.

## Why?

The Visual Studio Installer manages thousands of components and runs installers that write to the registry and to locations all over the filesystem. msvcup downloads the same `.vsix`, `.msi` and `.cab` packages the Visual Studio Installer does, but instead of running them it extracts their contents into a directory you choose, without executing any installer or other code from the packages. That directory is just files: delete it to uninstall, copy it, or keep several with different versions side by side.

Each install saves a lock file that contains the URL and SHA-256 hash of every package. Commit it to source control and everyone gets the same toolchain.

- **Fast**: Runs in milliseconds when already installed. Put it at the start of every build script.
- **Reproducible**: The lock file pins every download by URL and hash.
- **Isolated**: Everything goes into one directory. No registry modifications. No installers. No conflicts.
- **Cross-compilation**: Target x64, arm64, or x86 out of the box.
- **Minimal**: Download only what's needed to get a working native toolchain/SDK.

## Quick Start

- for CMake projects, see [examples/cmake/build.bat](examples/cmake/build.bat)
- for "handmade" style projects, see [examples/handmade/build.bat](examples/handmade/build.bat)

These examples contain batch scripts that download msvcup, install an MSVC/SDK, and then compile "hello.c". The cmake `build.bat` is also project agnostic, meaning it can be used to build most CMAKE projects with no changes.

After downloading msvcup, the example will install the toolchain and an SDK with a command like this:

```batch
> msvcup install msvc autoenv msvc-14.44.17.14 sdk-10.0.22621.7
```

That command would install the 3 packages "autoenv", "msvc-14.44.17.14" and "sdk-10.0.22621.7" to the "msvc" directory. It also creates a lock file named "msvc.lock" alongside that msvc directory. This lock file contains all the packages and payloads along with URL's and hashes for everything msvcup installs. This lock file is meant to be commited to source control and its content is a hashable representation of all the content msvcup installs along with the entirety of all info msvcup requires to download everything.

Use the `msvcup list` command to query the available packages/versions. Also note that msvcup caches everything it downloads into a global directory. Deleting the install directory and re-installing should require no network access.

## Visual Studio Command Prompts

The install directory will include the following 4 vcvars files:

- `vcvars-x64.bat`
- `vcvars-arm64.bat`
- `vcvars-x86.bat`
- `vcvars-arm.bat`

These scripts update the `INCLUDE`, `PATH` and `LIB` environment variables which is what transforms your shell into a "Visual Studio Command Prompt".

Note that if you include the "autoenv" package, your install directory will include `autoenv/$ARCH` subdi