vcpkg/docs/users/manifests.md

Manifest Mode

vcpkg has two modes of operation - classic mode and manifest mode.

In classic mode, vcpkg produces an "installed" tree, whose contents are changed by explicit calls to vcpkg install or vcpkg remove. The installed tree is intended for consumption by any number of projects: for example, installing a bunch of libraries and then using those libraries from Visual Studio, without additional configuration. Because the installed tree is not associated with an individual project, it's similar to tools like brew or apt, except that the installed tree is vcpkg-installation-local, rather than global to a system or user.

In manifest mode, an installed tree is associated with a particular project rather than the vcpkg installation. The set of installed ports is controlled by editing the project's "manifest file", and the installed tree is placed in the project directory or build directory. This mode acts more similarly to language package managers like Cargo, or npm. We recommend using this manifest mode whenever possible, because it allows one to encode a project's dependencies explicitly in a project file, rather than in the documentation, making your project much easier to consume.

Manifest mode is in beta, but it can be used from the CMake or MSBuild integration, which will be stable when used via things like find_package. This is the recommended way to use manifest mode.

Check out the manifest cmake example for an example project using CMake and manifest mode.

Table of Contents

• Simple Example Manifest
• Manifest Syntax Reference
• Command Line Interface
• CMake Integration
• MSBuild Integration

See also the original specification for more low-level details.

Simple Example Manifest

{
  "$schema": "https://raw.githubusercontent.com/microsoft/vcpkg/master/scripts/vcpkg.schema.json",
  "name": "my-application",
  "version": "0.15.2",
  "dependencies": [
    "boost-system",
    {
      "name": "cpprestsdk",
      "default-features": false
    },
    "libxml2",
    "yajl"
  ]
}

Manifest Syntax Reference

A manifest is a JSON-formatted file named vcpkg.json which lies at the root of your project. It contains all the information a person needs to know to get dependencies for your project, as well as all the metadata about your project that a person who depends on you might be interested in.

Manifests follow strict JSON: they can't contain C++-style comments (//) nor trailing commas. However you can use field names that start with $ to write your comments in any object that has a well-defined set of keys. These comment fields are not allowed in any objects which permit user-defined keys (such as "features").

Each manifest contains a top level object with the fields documented below; the most important ones are "name", the version fields, and "dependencies":

"name"

This is the name of your project! It must be formatted in a way that vcpkg understands - in other words, it must be lowercase alphabetic characters, digits, and hyphens, and it must not start nor end with a hyphen. For example, Boost.Asio might be given the name boost-asio.

This is a required field.

Version fields

There is, at this point, only one version field - "version-string". However, more will be added in the future. You must have one (and only one) version field. There are different reasons to use each version field:

• "version-string" - used for packages that don't have orderable versions. This is pretty uncommon, but since we don't have any versioning constraints yet, this is the only one that you can use.

Additionally, the "port-version" field is used by registries of packages, as a way to version "the package gotten from vcpkg install" differently from the upstream package version. You shouldn't need to worry about this at all.

Additional version fields

Experimental behind the versions feature flag

See versioning.md for additional version types.

"description"

This is where you describe your project. Give it a good description to help in searching for it! This can be a single string, or it can be an array of strings; in the latter case, the first string is treated as a summary, while the remaining strings are treated as the full description.

"builtin-baseline"

Experimental behind the versions feature flag

This field indicates the commit of vcpkg which provides global minimum version information for your manifest. It is required for top-level manifest files using versioning.

See also versioning for more semantic details.

"dependencies"

This field lists all the dependencies you'll need to build your library (as well as any your dependents might need, if they were to use you). It's an array of strings and objects:

• A string dependency (e.g., "dependencies": [ "zlib" ]) is the simplest way one can depend on a library; it means you don't depend on a single version, and don't need to write down any more information.
• On the other hand, an object dependency (e.g., "dependencies": [ { "name": "zlib" } ]) allows you to add that extra information.

Example:

"dependencies": [
  {
    "name": "arrow",
    "default-features": false,
    "features": [ "json" ]
  },
  "boost-asio",
  "openssl",
  {
    "name": "picosha2",
    "platform": "!windows"
  }
]

"name" Field

The name of the dependency. This follows the same restrictions as the "name" property for a project.

"features" and "default-features" Fields

"features" is an array of feature names which tell you the set of features that the dependencies need to have at a minimum, while "default-features" is a boolean that tells vcpkg whether or not to install the features the package author thinks should be "most common for most people to use".

For example, ffmpeg is a library which supports many, many audio and video codecs; however, for your specific project, you may only need mp3 encoding. Then, you might just ask for:

{
  "name": "ffmpeg",
  "default-features": false,
  "features": [ "mp3lame" ]
}

"platform" Field

The "platform" field defines the platforms where the dependency should be installed - for example, you might need to use sha256, and so you use platform primitives on Windows, but picosha2 on non-Windows platforms.

{
  "name": "picosha2",
  "platform": "!windows"
}

This is a string field which takes boolean expressions of the form <identifier>, !expression, expression { & expression & expression...}, and expression { | expression | expression...}, along with parentheses to denote precedence. For example, a dependency that's only installed on the Windows OS, for the ARM64 architecture, and on Linux on x64, would be written (windows & arm64) | (linux & x64).

The common identifiers are:

• The operating system: windows, uwp, linux, osx (includes macOS), android, emscripten
• The architecture: x86, x64, wasm32, arm64, arm (includes both arm32 and arm64 due to backwards compatibility)

although one can define their own.

"version>=" Field

Experimental behind the versions feature flag

A minimum version constraint on the dependency.

This field specifies the minimum version of the dependency using a '#' suffix to denote port-version if non-zero.

See also versioning for more semantic details.

"overrides"

Experimental behind the versions feature flag

This field enables version resolution to be ignored for certain dependencies and to use specific versions instead.

See also versioning for more semantic details.

Example:

  "overrides": [
    {
      "name": "arrow", "version": "1.2.3", "port-version": 7
    }
  ]

"supports"

If your project doesn't support common platforms, you can tell your users this with the "supports" field. It uses the same platform expressions as "platform", from dependencies, as well as the "supports" field of features. For example, if your library doesn't support linux, you might write { "supports": "!linux" }.

"features" and "default-features"

The "features" field defines your project's optional features, that others may either depend on or not. It's an object, where the keys are the names of the features, and the values are objects describing the feature. "description" is required, and acts exactly like the "description" field on the global package, and "dependencies" are optional, and again act exactly like the "dependencies" field on the global package. There's also the "supports" field, which again acts exactly like the "supports" field on the global package.

You also have control over which features are default, if a person doesn't ask for anything specific, and that's the "default-features" field, which is an array of feature names.

Example:

{
  "name": "libdb",
  "version": "1.0.0",
  "description": [
    "An example database library.",
    "Optionally can build with CBOR, JSON, or CSV as backends."
  ],
  "$default-features-explanation": "Users using this library transitively will get all backends automatically",
  "default-features": [ "cbor", "csv", "json" ],
  "features": {
    "cbor": {
      "description": "The CBOR backend",
      "dependencies": [
        {
          "$explanation": [
            "This is how you tell vcpkg that the cbor feature depends on the json feature of this package"
          ],
          "name": "libdb",
          "default-features": false,
          "features": [ "json" ]
        }
      ]
    },
    "csv": {
      "description": "The CSV backend",
      "dependencies": [
        "fast-cpp-csv-parser"
      ]
    },
    "json": {
      "description": "The JSON backend",
      "dependencies": [
        "jsoncons"
      ]
    }
  }
}

Command Line Interface

Experimental behind the manifests feature flag

When invoked from any subdirectory of the directory containing vcpkg.json, vcpkg install with no package arguments will install all manifest dependencies into <directory containing vcpkg.json>/vcpkg_installed/. Most of vcpkg install's classic mode parameters function the same in manifest mode.

--x-install-root=<path>

Experimental and may change or be removed at any time

Specifies an alternate install location than <directory containing vcpkg.json>/vcpkg_installed/.

--triplet=<triplet>

Specify the triplet to be used for installation.

Defaults to the same default triplet as in classic mode.

--x-feature=<feature>

Experimental and may change or be removed at any time

Specify an additional feature from the vcpkg.json to install dependencies from.

--x-no-default-features

Experimental and may change or be removed at any time

Disables automatic activation of all default features listed in the vcpkg.json.

--x-manifest-root=<path>

Experimental and may change or be removed at any time

Specifies the directory containing vcpkg.json.

Defaults to searching upwards from the current working directory.

CMake Integration

Our CMake Integration will automatically detect a vcpkg.json manifest file in the same directory as the top-level CMakeLists.txt (${CMAKE_SOURCE_DIR}/vcpkg.json) and activate manifest mode. Vcpkg will be automatically bootstrapped if missing and invoked to install your dependencies into your local build directory (${CMAKE_BINARY_DIR}/vcpkg_installed).

Configuration

All vcpkg-affecting variables must be defined before the first project() directive, such as via the command line or set() statements.

VCPKG_TARGET_TRIPLET

This variable controls which triplet dependencies will be installed for.

If unset, vcpkg will automatically detect an appropriate default triplet given the current compiler settings.

VCPKG_HOST_TRIPLET

This variable controls which triplet host dependencies will be installed for.

If unset, vcpkg will automatically detect an appropriate native triplet (x64-windows, x64-osx, x64-linux).

See also Host Dependencies.

VCPKG_MANIFEST_MODE

This variable controls whether vcpkg operates in manifest mode or in classic mode. To disable manifest mode even with a vcpkg.json, set this to OFF.

Defaults to ON when VCPKG_MANIFEST_DIR is non-empty or ${CMAKE_SOURCE_DIR}/vcpkg.json exists.

VCPKG_MANIFEST_DIR

This variable can be defined to specify an alternate folder containing your vcpkg.json manifest.

Defaults to ${CMAKE_SOURCE_DIR} if ${CMAKE_SOURCE_DIR}/vcpkg.json exists.

VCPKG_MANIFEST_INSTALL

This variable controls whether vcpkg will be automatically run to install your dependencies during your configure step.

Defaults to ON if VCPKG_MANIFEST_MODE is ON.

VCPKG_BOOTSTRAP_OPTIONS

This variable can be set to additional command parameters to pass to ./bootstrap-vcpkg (run in automatic restore mode if the vcpkg tool does not exist).

VCPKG_OVERLAY_TRIPLETS

This variable can be set to a list of paths to be passed on the command line as --overlay-triplets=...

VCPKG_OVERLAY_PORTS

This variable can be set to a list of paths to be passed on the command line as --overlay-ports=...

VCPKG_MANIFEST_FEATURES

This variable can be set to a list of features to treat as active when installing from your manifest.

For example, Features can be used by projects to control building with additional dependencies to enable tests or samples:

{
  "name": "mylibrary",
  "version": "1.0",
  "dependencies": [ "curl" ],
  "features": {
    "samples": {
      "description": "Build Samples",
      "dependencies": [ "fltk" ]
    },
    "tests": {
      "description": "Build Tests",
      "dependencies": [ "gtest" ]
    }
  }
}

# CMakeLists.txt

option(BUILD_TESTING "Build tests" OFF)
if(BUILD_TESTING)
  list(APPEND VCPKG_MANIFEST_FEATURES "tests")
endif()

option(BUILD_SAMPLES "Build samples" OFF)
if(BUILD_SAMPLES)
  list(APPEND VCPKG_MANIFEST_FEATURES "samples")
endif()

project(myapp)

# ...

VCPKG_MANIFEST_NO_DEFAULT_FEATURES

This variable controls whether to automatically activate all default features in addition to those listed in VCPKG_MANIFEST_FEATURES. If set to ON, default features will not be automatically activated.

Defaults to OFF.

VCPKG_INSTALL_OPTIONS

This variable can be set to a list of additional command line parameters to pass to the vcpkg tool during automatic installation.

VCPKG_FEATURE_FLAGS

This variable can be set to a list of feature flags to pass to the vcpkg tool during automatic installation to opt-in to experimental behavior.

See the --feature-flags= command line option for more information.

MSBuild Integration

To use manifests with MSBuild, first you need to use an existing integration method. Then, simply add a vcpkg.json above your project file (such as in the root of your source repository) and set the property VcpkgEnableManifest to true. You can set this property via the IDE in Project Properties -> Vcpkg -> Use Vcpkg Manifest.

As part of your project's build, vcpkg automatically be run and install any listed dependencies to vcpkg_installed/ adjacent to the vcpkg.json file; these files will then automatically be included in and linked to your MSBuild projects.

Note: It is critical that all project files in a single build consuming the same vcpkg.json use the same triplet; if you need to use different triplets for different projects in your solution, they must consume from different vcpkg.json files.

MSBuild Properties

These properties can be defined via the VS GUI under Project Properties -> Vcpkg or via a common .props file.

VcpkgEnabled (Use Vcpkg)

This can be set to "false" to explicitly disable vcpkg integration for the project

VcpkgTriplet (Triplet)

This can be set to a custom triplet to use for integration (such as x64-windows-static)

VcpkgHostTriplet (Host Triplet)

This can be set to a custom triplet to use for resolving host dependencies.

If unset, this will default to the "native" triplet (x64-windows, x64-osx, x64-linux).

See also Host Dependencies.

VcpkgAdditionalInstallOptions (Additional Options)

When using a manifest, this option specifies additional command line flags to pass to the underlying vcpkg tool invocation. This can be used to access features that have not yet been exposed through another option.

VcpkgConfiguration (Vcpkg Configuration)

If your configuration names are too complex for vcpkg to guess correctly, you can assign this property to Release or Debug to explicitly tell vcpkg what variant of libraries you want to consume.

VcpkgEnableManifest (Use Vcpkg Manifest)

This property must be set to true in order to consume from a local vcpkg.json file. If set to false, any local vcpkg.json files will be ignored. This will default to true in the future.

VcpkgManifestInstall (Install Vcpkg Dependencies)

(Requires Use Vcpkg Manifest set to true)

This property can be set to "false" to disable automatic dependency restoration on project build. Dependencies can be manually restored via the vcpkg command line.

VcpkgInstalledDirectory (Installed Directory)

This property defines the location where headers and binaries are consumed from. In manifest mode, this directory is created and populated based on your manifest.