cmake-presets(7)

• Introduction
• Format
• Schema

Introduction

One problem that CMake users often face is sharing settings with other people for common ways to configure a project. This may be done to support CI builds, or for users who frequently use the same build. CMake supports two files, CMakePresets.json and CMakeUserPresets.json, that allow users to specify common configure options and share them with others.

CMakePresets.json and CMakeUserPresets.json live in the project’s root directory. They both have exactly the same format, and both are optional (though at least one must be present if --preset is specified.) CMakePresets.json is meant to save project-wide builds, while CMakeUserPresets.json is meant for developers to save their own local builds. CMakePresets.json may be checked into a version control system, and CMakeUserPresets.json should NOT be checked in. For example, if a project is using Git, CMakePresets.json may be tracked, and CMakeUserPresets.json should be added to the .gitignore.

Format

The files are a JSON document with an object as the root:

{
  "version": 1,
  "cmakeMinimumRequired": {
    "major": 3,
    "minor": 19,
    "patch": 0
  },
  "configurePresets": [
    {
      "name": "default",
      "displayName": "Default Config",
      "description": "Default build using Ninja generator",
      "generator": "Ninja",
      "binaryDir": "${sourceDir}/build/default",
      "cacheVariables": {
        "FIRST_CACHE_VARIABLE": {
          "type": "BOOL",
          "value": "OFF"
        },
        "SECOND_CACHE_VARIABLE": "ON"
      },
      "environment": {
        "MY_ENVIRONMENT_VARIABLE": "Test",
        "PATH": "$env{HOME}/ninja/bin:$penv{PATH}"
      },
      "vendor": {
        "example.com/ExampleIDE/1.0": {
          "autoFormat": true
        }
      }
    },
    {
      "name": "ninja-multi",
      "inherits": "default",
      "displayName": "Ninja Multi-Config",
      "description": "Default build using Ninja Multi-Config generator",
      "generator": "Ninja Multi-Config"
    }
  ],
  "vendor": {
    "example.com/ExampleIDE/1.0": {
      "autoFormat": false
    }
  }
}

The root object recognizes the following fields:

version

A required integer representing the version of the JSON schema. Currently, the only supported version is 1.

cmakeMinimumRequired

An optional object representing the minimum version of CMake needed to build this project. This object consists of the following fields:

major

An optional integer representing the major version.

minor

An optional integer representing the minor version.

patch

An optional integer representing the patch version.

vendor

An optional map containing vendor-specific information. CMake does not interpret the contents of this field except to verify that it is a map if it does exist. However, the keys should be a vendor-specific domain name followed by a /-separated path. For example, the Example IDE 1.0 could use example.com/ExampleIDE/1.0. The value of each field can be anything desired by the vendor, though will typically be a map.

configurePresets

An optional array of configure preset objects. Each preset may contain the following fields:

name

A required string representing the machine-friendly name of the preset. This identifier is used in the --preset argument. There must not be two presets in the union of CMakePresets.json and CMakeUserPresets.json in the same directory with the same name.

hidden

An optional boolean specifying whether or not a preset should be hidden. If a preset is hidden, it cannot be used in the --preset= argument, will not show up in the CMake GUI, and does not have to have a valid generator or binaryDir, even from inheritance. hidden presets are intended to be used as a base for other presets to inherit via the inherits field.

inherits

An optional array of strings representing the names of presets to inherit from. The preset will inherit all of the fields from the inherits presets by default (except name, hidden, inherits, description, and longDescription), but can override them as desired. If multiple inherits presets provide conflicting values for the same field, the earlier preset in the inherits list will be preferred. Presets in CMakePresets.json may not inherit from presets in CMakeUserPresets.json.

This field can also be a string, which is equivalent to an array containing one string.

vendor

An optional map containing vendor-specific information. CMake does not interpret the contents of this field except to verify that it is a map if it does exist. However, it should follow the same conventions as the root-level vendor field. If vendors use their own per-preset vendor field, they should implement inheritance in a sensible manner when appropriate.

displayName

An optional string with a human-friendly name of the preset.

description

An optional string with a human-friendly description of the preset.

generator

An optional string representing the generator to use for the preset. If generator is not specified, it must be inherited from the inherits preset (unless this preset is hidden).

Note that for Visual Studio generators, unlike in the command line -G argument, you cannot include the platform name in the generator name. Use the architecture field instead.

architecture toolset

Optional fields representing the platform and toolset, respectively, for generators that support them. Each may be either a string or an object with the following fields:

value

An optional string representing the value.

strategy

An optional string telling CMake how to handle the architecture or toolset field. Valid values are:

"set"

Set the respective value. This will result in an error for generators that do not support the respective field.

"external"

Do not set the value, even if the generator supports it. This is useful if, for example, a preset uses the Ninja generator, and an IDE knows how to set up the Visual C++ environment from the architecture and toolset fields. In that case, CMake will ignore the field, but the IDE can use them to set up the environment before invoking CMake.

binaryDir

An optional string representing the path to the output binary directory. This field supports macro expansion. If a relative path is specified, it is calculated relative to the source directory. If binaryDir is not specified, it must be inherited from the inherits preset (unless this preset is hidden).

cmakeExecutable

An optional string representing the path to the CMake executable to use for this preset. This is reserved for use by IDEs, and is not used by CMake itself. IDEs that use this field should expand any macros in it.

cacheVariables

An optional map of cache variables. The key is the variable name (which may not be an empty string), and the value is either null, a boolean (which is equivalent to a value of "TRUE" or "FALSE" and a type of BOOL), a string representing the value of the variable (which supports macro expansion), or an object with the following fields:

type

An optional string representing the type of the variable.

value

A required string or boolean representing the value of the variable. A boolean is equivalent to "TRUE" or "FALSE". This field supports macro expansion.

Cache variables are inherited through the inherits field, and the preset’s variables will be the union of its own cacheVariables and the cacheVariables from all its parents. If multiple presets in this union define the same variable, the standard rules of inherits are applied. Setting a variable to null causes it to not be set, even if a value was inherited from another preset.

environment

An optional map of environment variables. The key is the variable name (which may not be an empty string), and the value is either null or a string representing the value of the variable. Each variable is set regardless of whether or not a value was given to it by the process’s environment. This field supports macro expansion, and environment variables in this map may reference each other, and may be listed in any order, as long as such references do not cause a cycle (for example, if ENV_1 is $env{ENV_2}, ENV_2 may not be $env{ENV_1}.)

Environment variables are inherited through the inherits field, and the preset’s environment will be the union of its own environment and the environment from all its parents. If multiple presets in this union define the same variable, the standard rules of inherits are applied. Setting a variable to null causes it to not be set, even if a value was inherited from another preset.

warnings

An optional object specifying the warnings to enable. The object may contain the following fields:

dev

An optional boolean. Equivalent to passing -Wdev or -Wno-dev on the command line. This may not be set to false if errors.dev is set to true.

deprecated

An optional boolean. Equivalent to passing -Wdeprecated or -Wno-deprecated on the command line. This may not be set to false if errors.deprecated is set to true.

uninitialized

An optional boolean. Setting this to true is equivalent to passing --warn-uninitialized on the command line.

unusedCli

An optional boolean. Setting this to false is equivalent to passing --no-warn-unused-cli on the command line.

systemVars

An optional boolean. Setting this to true is equivalent to passing --check-system-vars on the command line.

errors

An optional object specifying the errors to enable. The object may contain the following fields:

dev

An optional boolean. Equivalent to passing -Werror=dev or -Wno-error=dev on the command line. This may not be set to true if warnings.dev is set to false.

deprecated

An optional boolean. Equivalent to passing -Werror=deprecated or -Wno-error=deprecated on the command line. This may not be set to true if warnings.deprecated is set to false.

debug

An optional object specifying debug options. The object may contain the following fields:

output

An optional boolean. Setting this to true is equivalent to passing --debug-output on the command line.

tryCompile

An optional boolean. Setting this to true is equivalent to passing --debug-trycompile on the command line.

find

An optional boolean. Setting this to true is equivalent to passing --debug-find on the command line.

As mentioned above, some fields support macro expansion. Macros are recognized in the form $<macro-namespace>{<macro-name>}. All macros are evaluated in the context of the preset being used, even if the macro is in a field that was inherited from another preset. For example, if the Base preset sets variable PRESET_NAME to ${presetName}, and the Derived preset inherits from Base, PRESET_NAME will be set to Derived.

It is an error to not put a closing brace at the end of a macro name. For example, ${sourceDir is invalid. A dollar sign ($) followed by anything other than a left curly brace ({) with a possible namespace is interpreted as a literal dollar sign.

Recognized macros include:

${sourceDir}

Path to the project source directory.

${sourceParentDir}

Path to the project source directory’s parent directory.

${sourceDirName}

The last filename component of ${sourceDir}. For example, if ${sourceDir} is /path/to/source, this would be source.

${presetName}

Name specified in the preset’s name field.

${generator}

Generator specified in the preset’s generator field.

${dollar}

A literal dollar sign ($).

$env{<variable-name>}

Environment variable with name <variable-name>. The variable name may not be an empty string. If the variable is defined in the environment field, that value is used instead of the value from the parent environment. If the environment variable is not defined, this evaluates as an empty string.

Note that while Windows environment variable names are case-insensitive, variable names within a preset are still case-sensitive. This may lead to unexpected results when using inconsistent casing. For best results, keep the casing of environment variable names consistent.

$penv{<variable-name>}

Similar to $env{<variable-name>}, except that the value only comes from the parent environment, and never from the environment field. This allows you to prepend or append values to existing environment variables. For example, setting PATH to /path/to/ninja/bin:$penv{PATH} will prepend /path/to/ninja/bin to the PATH environment variable. This is needed because $env{<variable-name>} does not allow circular references.

$vendor{<macro-name>}

An extension point for vendors to insert their own macros. CMake will not be able to use presets which have a $vendor{<macro-name>} macro, and effectively ignores such presets. However, it will still be able to use other presets from the same file.

CMake does not make any attempt to interpret $vendor{<macro-name>} macros. However, to avoid name collisions, IDE vendors should prefix <macro-name> with a very short (preferably <= 4 characters) vendor identifier prefix, followed by a ., followed by the macro name. For example, the Example IDE could have $vendor{xide.ideInstallDir}.

Schema

This file provides a machine-readable JSON schema for the CMakePresets.json format.