NAME

cmake-presets - CMakePresets.json

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": 3,
  "cmakeMinimumRequired": {
    "major": 3,
    "minor": 21,
    "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:$penv{PATH}"
      },
      "vendor": {
        "example.com/ExampleIDE/1.0": {
          "autoFormat": true
        }
      }
    },
    {
      "name": "ninja-multi",
      "inherits": "default",
      "displayName": "Ninja Multi-Config",
      "description": "Default build using Ninja Multi-Config generator",
      "generator": "Ninja Multi-Config"
    },
    {
      "name": "windows-only",
      "inherits": "default",
      "displayName": "Windows-only configuration",
      "description": "This build is only available on Windows",
      "condition": {
        "type": "equals",
        "lhs": "${hostSystemName}",
        "rhs": "Windows"
      }
    }
  ],
  "buildPresets": [
    {
      "name": "default",
      "configurePreset": "default"
    }
  ],
  "testPresets": [
    {
      "name": "default",
      "configurePreset": "default",
      "output": {"outputOnFailure": true},
      "execution": {"noTestsAction": "error", "stopOnFailure": true}
    }
  ],
  "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. The supported versions are 1, 2, and 3.

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. This is allowed in preset files specifying version 1 or above.

buildPresets

An optional array of Build Preset objects. This is allowed in preset files specifying version 2 or above.

testPresets

An optional array of Test Preset objects. This is allowed in preset files specifying version 2 or above.

Configure Preset

Each entry of the configurePresets array is a JSON object that may contain the following fields:

name

A required string representing the machine-friendly name of the preset. This identifier is used in the cmake --preset option. There must not be two configure presets in the union of CMakePresets.json and CMakeUserPresets.json in the same directory with the same name. However, a configure preset may have the same name as a build or test preset.

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 displayName), 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.

condition

An optional Condition object. This is allowed in preset files specifying version 3 or above.

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). In version 3 or above, this field may be omitted to fall back to regular generator discovery procedure.

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.

toolchainFile

An optional string representing the path to the toolchain file. This field supports macro expansion. If a relative path is specified, it is calculated relative to the build directory, and if not found, relative to the source directory. This field takes precedence over any CMAKE_TOOLCHAIN_FILE value. It is allowed in preset files specifying version 3 or above.

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). In version 3 or above, this field may be omitted.

installDir

An optional string representing the path to the installation directory. This field supports macro expansion. If a relative path is specified, it is calculated relative to the source directory. This is allowed in preset files specifying version 3 or above.

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.

Build Preset

Each entry of the buildPresets array is a JSON object that may contain the following fields:

name

A required string representing the machine-friendly name of the preset. This identifier is used in the cmake --build --preset option. There must not be two build presets in the union of CMakePresets.json and CMakeUserPresets.json in the same directory with the same name. However, a build preset may have the same name as a configure or test preset.

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 and does not have to have a valid configurePreset, even from inheritance. hidden presets are intended to be used as a base for other presets to inherit via the inherits field.

inherits

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

condition

An optional Condition object. This is allowed in preset files specifying version 3 or above.

vendor

displayName

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

description

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

NOTE:

For a CMake project using ExternalProject with a configuration preset having environment variables needed in the ExternalProject, use a build preset that inherits that configuration preset or the ExternalProject will not have the environment variables set in the configuration preset. Example: suppose the host defaults to one compiler (say Clang) and the user wishes to use another compiler (say GCC). Set configuration preset environment variables CC and CXX and use a build preset that inherits that configuration preset. Otherwise the ExternalProject may use a different (system default) compiler than the top-level CMake project.

configurePreset

An optional string specifying the name of a configure preset to associate with this build preset. If configurePreset is not specified, it must be inherited from the inherits preset (unless this preset is hidden). The build directory is inferred from the configure preset, so the build will take place in the same binaryDir that the configuration did.

inheritConfigureEnvironment

An optional boolean that defaults to true. If true, the environment variables from the associated configure preset are inherited after all inherited build preset environments, but before environment variables explicitly specified in this build preset.

jobs

An optional integer. Equivalent to passing --parallel or -j on the command line.

targets

An optional string or array of strings. Equivalent to passing --target or -t on the command line. Vendors may ignore the targets property or hide build presets that explicitly specify targets. This field supports macro expansion.

configuration

An optional string. Equivalent to passing --config on the command line.

cleanFirst

An optional bool. If true, equivalent to passing --clean-first on the command line.

verbose

An optional bool. If true, equivalent to passing --verbose on the command line.

nativeToolOptions

An optional array of strings. Equivalent to passing options after -- on the command line. The array values support macro expansion.

Test Preset

Each entry of the testPresets array is a JSON object that may contain the following fields:

name

A required string representing the machine-friendly name of the preset. This identifier is used in the ctest --preset option. There must not be two test presets in the union of CMakePresets.json and CMakeUserPresets.json in the same directory with the same name. However, a test preset may have the same name as a configure or build preset.

hidden

inherits

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

condition

An optional Condition object. This is allowed in preset files specifying version 3 or above.

vendor

displayName

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

description

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

configurePreset

An optional string specifying the name of a configure preset to associate with this test preset. If configurePreset is not specified, it must be inherited from the inherits preset (unless this preset is hidden). The build directory is inferred from the configure preset, so tests will run in the same binaryDir that the configuration did and build did.

inheritConfigureEnvironment

An optional boolean that defaults to true. If true, the environment variables from the associated configure preset are inherited after all inherited test preset environments, but before environment variables explicitly specified in this test preset.

configuration

An optional string. Equivalent to passing --build-config on the command line.

overwriteConfigurationFile

An optional array of configuration options to overwrite options specified in the CTest configuration file. Equivalent to passing --overwrite for each value in the array. The array values support macro expansion.

output

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

shortProgress

An optional bool. If true, equivalent to passing --progress on the command line.

verbosity

An optional string specifying verbosity level. Must be one of the following:

default

Equivalent to passing no verbosity flags on the command line.

verbose

Equivalent to passing --verbose on the command line.

extra

Equivalent to passing --extra-verbose on the command line.

debug

An optional bool. If true, equivalent to passing --debug on the command line.

outputOnFailure

An optional bool. If true, equivalent to passing --output-on-failure on the command line.

quiet

An optional bool. If true, equivalent to passing --quiet on the command line.

outputLogFile

An optional string specifying a path to a log file. Equivalent to passing --output-log on the command line. This field supports macro expansion.

labelSummary

An optional bool. If false, equivalent to passing --no-label-summary on the command line.

subprojectSummary

An optional bool. If false, equivalent to passing --no-subproject-summary on the command line.

maxPassedTestOutputSize

An optional integer specifying the maximum output for passed tests in bytes. Equivalent to passing --test-output-size-passed on the command line.

maxFailedTestOutputSize

An optional integer specifying the maximum output for failed tests in bytes. Equivalent to passing --test-output-size-failed on the command line.

maxTestNameWidth

An optional integer specifying the maximum width of a test name to output. Equivalent to passing --max-width on the command line.

filter

An optional object specifying how to filter the tests to run. The object may contain the following fields.

include

An optional object specifying which tests to include. The object may contain the following fields.

name

An optional string specifying a regex for test names. Equivalent to passing --tests-regex on the command line. This field supports macro expansion. CMake regex syntax is described under string(REGEX).

label

An optional string specifying a regex for test labels. Equivalent to passing --label-regex on the command line. This field supports macro expansion.

useUnion

An optional bool. Equivalent to passing --union on the command line.

index

An optional object specifying tests to include by test index. The object may contain the following fields. Can also be an optional string specifying a file with the command line syntax for --tests-information. If specified as a string, this field supports macro expansion.

start

An optional integer specifying a test index to start testing at.

end

An optional integer specifying a test index to stop testing at.

stride

An optional integer specifying the increment.

specificTests

An optional array of integers specifying specific test indices to run.

exclude

An optional object specifying which tests to exclude. The object may contain the following fields.

name

An optional string specifying a regex for test names. Equivalent to passing --exclude-regex on the command line. This field supports macro expansion.

label

An optional string specifying a regex for test labels. Equivalent to passing --label-exclude on the command line. This field supports macro expansion.

fixtures

An optional object specifying which fixtures to exclude from adding tests. The object may contain the following fields.

any

An optional string specifying a regex for text fixtures to exclude from adding any tests. Equivalent to --fixture-exclude-any on the command line. This field supports macro expansion.

setup

An optional string specifying a regex for text fixtures to exclude from adding setup tests. Equivalent to --fixture-exclude-setup on the command line. This field supports macro expansion.

cleanup

An optional string specifying a regex for text fixtures to exclude from adding cleanup tests. Equivalent to --fixture-exclude-cleanup on the command line. This field supports macro expansion.

execution

An optional object specifying options for test execution. The object may contain the following fields.

stopOnFailure

An optional bool. If true, equivalent to passing --stop-on-failure on the command line.

enableFailover

An optional bool. If true, equivalent to passing -F on the command line.

jobs

An optional integer. Equivalent to passing --parallel on the command line.

resourceSpecFile

An optional string. Equivalent to passing --resource-spec-file on the command line. This field supports macro expansion.

testLoad

An optional integer. Equivalent to passing --test-load on the command line.

showOnly

An optional string. Equivalent to passing --show-only on the command line. The string must be one of the following values:

human

json-v1

repeat

An optional object specifying how to repeat tests. Equivalent to passing --repeat on the command line. The object must have the following fields.

mode

A required string. Must be one of the following values:

until-fail

until-pass

after-timeout

count

A required integer.

interactiveDebugging

An optional bool. If true, equivalent to passing --interactive-debug-mode 1 on the command line. If false, equivalent to passing --interactive-debug-mode 0 on the command line.

scheduleRandom

An optional bool. If true, equivalent to passing --schedule-random on the command line.

timeout

An optional integer. Equivalent to passing --timeout on the command line.

noTestsAction

An optional string specifying the behavior if no tests are found. Must be one of the following values:

default

Equivalent to not passing any value on the command line.

error

Equivalent to passing --no-tests=error on the command line.

ignore

Equivalent to passing --no-tests=ignore on the command line.

Condition

The condition field of a preset, allowed in preset files specifying version 3 or above, is used to determine whether or not the preset is enabled. For example, this can be used to disable a preset on platforms other than Windows. condition may be either a boolean, null, or an object. If it is a boolean, the boolean indicates whether the preset is enabled or disabled. If it is null, the preset is enabled, but the null condition is not inherited by any presets that may inherit from the preset. Sub-conditions (for example in a not, anyOf, or allOf condition) may not be null. If it is an object, it has the following fields:

type

A required string with one of the following values:

"const"

Indicates that the condition is constant. This is equivalent to using a boolean in place of the object. The condition object will have the following additional fields:

value

A required boolean which provides a constant value for the condition's evaluation.

"equals"

"notEquals"

Indicates that the condition compares two strings to see if they are equal (or not equal). The condition object will have the following additional fields:

lhs

First string to compare. This field supports macro expansion.

rhs

Second string to compare. This field supports macro expansion.

"inList"

"notInList"

Indicates that the condition searches for a string in a list of strings. The condition object will have the following additional fields:

string

A required string to search for. This field supports macro expansion.

list

A required list of strings to search. This field supports macro expansion, and uses short-circuit evaluation.

"matches"

"notMatches"

Indicates that the condition searches for a regular expression in a string. The condition object will have the following additional fields:

string

A required string to search. This field supports macro expansion.

regex

A required regular expression to search for. This field supports macro expansion.

"anyOf"

"allOf"

Indicates that the condition is an aggregation of zero or more nested conditions. The condition object will have the following additional fields:

conditions

A required array of condition objects. These conditions use short-circuit evaluation.

"not"

Indicates that the condition is an inversion of another condition. The condition object will have the following additional fields:

condition

A required condition object.

Macro Expansion

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. For build and test presets, this will evaluate to the generator specified by configurePreset.

${hostSystemName}

The name of the host operating system. Contains the same value as CMAKE_HOST_SYSTEM_NAME. This is allowed in preset files specifying version 3 or above.

${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.

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