CMAKE-ENV-VARIABLES(7)

NAME
cmake-env-variables - CMake Environment Variables Reference

This page lists environment variables that have special meaning to CMake.

For general information on environment variables, see the Environment Variables section in the cmake-language manual.

ENVIRONMENT VARIABLES THAT CHANGE BEHAVIOR

  CMAKE_PREFIX_PATH

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

The CMAKE_PREFIX_PATH environment variable may be set to a list of directories specifying installation prefixes to be searched by the find_package(), find_program(), find_library(), find_file(), and find_path() commands. Each command will add appropriate subdirectories (like bin, lib, or include) as specified in its own documentation.

This variable may hold a single prefix or a list of prefixes separated by : on UNIX or ; on Windows (the same as the PATH environment variable convention on those platforms).

See also the CMAKE_PREFIX_PATH CMake variable.

ENVIRONMENT VARIABLES THAT CONTROL THE BUILD

  CMAKE_APPLE_SILICON_PROCESSOR

New in version 3.19.2.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

On Apple Silicon hosts running macOS, set this environment variable to tell CMake what architecture to use for CMAKE_HOST_SYSTEM_PROCESSOR. The value must be either arm64 or x86_64.

The CMAKE_APPLE_SILICON_PROCESSOR normal variable, if set, overrides this environment variable.

  CMAKE_BUILD_PARALLEL_LEVEL

New in version 3.12.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Specifies the maximum number of concurrent processes to use when building using the cmake --build command line Build Tool Mode.

If this variable is defined empty the native build tool’s default number is used.

  CMAKE_CONFIG_TYPE

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

The default build configuration for Build Tool Mode and ctest build handler when there is no explicit configuration given.

  CMAKE_EXPORT_COMPILE_COMMANDS

New in version 3.17.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

The default value for CMAKE_EXPORT_COMPILE_COMMANDS when there is no explicit configuration given on the first run while creating a new build tree. On later runs in an existing build tree the value persists in the cache as CMAKE_EXPORT_COMPILE_COMMANDS.

  CMAKE_GENERATOR

New in version 3.15.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Specifies the CMake default generator to use when no generator is supplied with -G. If the provided value doesn’t name a generator known by CMake, the internal default is used. Either way the resulting generator selection is stored in the CMAKE_GENERATOR variable.

Some generators may be additionally configured using the environment variables:

•   CMAKE_GENERATOR_PLATFORM

•   CMAKE_GENERATOR_TOOLSET

•   CMAKE_GENERATOR_INSTANCE

  CMAKE_GENERATOR_INSTANCE

New in version 3.15.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default value for CMAKE_GENERATOR_INSTANCE if no Cache entry is present. This value is only applied if CMAKE_GENERATOR is set.

  CMAKE_GENERATOR_PLATFORM

New in version 3.15.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default value for CMAKE_GENERATOR_PLATFORM if no Cache entry is present and no value is specified by cmake(1) -A option. This value is only applied if CMAKE_GENERATOR is set.

  CMAKE_GENERATOR_TOOLSET

New in version 3.15.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default value for CMAKE_GENERATOR_TOOLSET if no Cache entry is present and no value is specified by cmake(1) -T option. This value is only applied if CMAKE_GENERATOR is set.

  CMAKE_<LANG>_COMPILER_LAUNCHER

New in version 3.17.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compiler launcher to use for the specified language. Will only be used by CMake to initialize the variable on the first configuration. Afterwards, it is available through the cache setting of the variable of the same name. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_<LANG>_COMPILER_LAUNCHER variable is defined.

  CMAKE_MSVCIDE_RUN_PATH

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Extra PATH locations for custom commands when using Visual Studio 9 2008 (or above) generators.

The CMAKE_MSVCIDE_RUN_PATH environment variable sets the default value for the CMAKE_MSVCIDE_RUN_PATH variable if not already explicitly set.

  CMAKE_NO_VERBOSE

New in version 3.14.

Disables verbose output from CMake when VERBOSE environment variable is set.

Only your build tool of choice will still print verbose output when you start to actually build your project.

  CMAKE_OSX_ARCHITECTURES

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Target specific architectures for macOS.

The CMAKE_OSX_ARCHITECTURES environment variable sets the default value for the CMAKE_OSX_ARCHITECTURES variable. See OSX_ARCHITECTURES for more information.

  DESTDIR

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

On UNIX one can use the DESTDIR mechanism in order to relocate the whole installation. DESTDIR means DESTination DIRectory. It is commonly used by makefile users in order to install software at non-default location. It is usually invoked like this:

make DESTDIR=/home/john install

which will install the concerned software using the installation prefix, e.g. /usr/local prepended with the DESTDIR value which finally gives /home/john/usr/local.

WARNING: DESTDIR may not be used on Windows because installation prefix usually contains a drive letter like in C:/Program Files which cannot be prepended with some other prefix.

  LDFLAGS

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Will only be used by CMake on the first configuration to determine the default linker flags, after which the value for LDFLAGS is stored in the cache as CMAKE_EXE_LINKER_FLAGS_INIT, CMAKE_SHARED_LINKER_FLAGS_INIT, and CMAKE_MODULE_LINKER_FLAGS_INIT. For any configuration run (including the first), the environment variable will be ignored if the equivalent CMAKE_<TYPE>_LINKER_FLAGS_INIT variable is defined.

  MACOSX_DEPLOYMENT_TARGET

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Specify the minimum version of macOS on which the target binaries are to be deployed.

The MACOSX_DEPLOYMENT_TARGET environment variable sets the default value for the CMAKE_OSX_DEPLOYMENT_TARGET variable.

  <PackageName>_ROOT

New in version 3.12.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Calls to find_package(<PackageName>) will search in prefixes specified by the <PackageName>_ROOT environment variable, where <PackageName> is the name given to the find_package() call and _ROOT is literal. For example, find_package(Foo) will search prefixes specified in the Foo_ROOT environment variable (if set). See policy CMP0074.

This variable may hold a single prefix or a list of prefixes separated by : on UNIX or ; on Windows (the same as the PATH environment variable convention on those platforms).

See also the <PackageName>_ROOT CMake variable.

  VERBOSE

New in version 3.14.

Activates verbose output from CMake and your build tools of choice when you start to actually build your project.

Note that any given value is ignored. It’s just checked for existence.

See also Build Tool Mode and CMAKE_NO_VERBOSE environment variable

ENVIRONMENT VARIABLES FOR LANGUAGES

  ASM<DIALECT>

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling a specific dialect of assembly language files. ASM<DIALECT> can be ASM, ASM_NASM (Netwide Assembler), ASM_MASM (Microsoft Assembler) or ASM-ATT (Assembler AT&T). Will only be used by CMake on the first configuration to determine ASM<DIALECT> compiler, after which the value for ASM<DIALECT> is stored in the cache as CMAKE_ASM<DIALECT>_COMPILER. For subsequent configuration runs, the environment variable will be ignored in favor of CMAKE_ASM<DIALECT>_COMPILER.

NOTE: Options that are required to make the compiler work correctly can be included; they can not be changed.

$ export ASM="custom-compiler --arg1 --arg2"

  ASM<DIALECT>FLAGS

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling a specific dialect of an assembly language. ASM<DIALECT>FLAGS can be ASMFLAGS, ASM_NASMFLAGS, ASM_MASMFLAGS or ASM-ATTFLAGS. Will only be used by CMake on the first configuration to determine ASM_<DIALECT> default compilation flags, after which the value for ASM<DIALECT>FLAGS is stored in the cache as CMAKE_ASM<DIALECT>_FLAGS <CMAKE_<LANG>_FLAGS>. For any configuration run (including the first), the environment variable will be ignored, if the CMAKE_ASM<DIALECT>_FLAGS <CMAKE_<LANG>_FLAGS> variable is defined.

See also CMAKE_ASM<DIALECT>_FLAGS_INIT.

  CC

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling C language files. Will only be used by CMake on the first configuration to determine C compiler, after which the value for CC is stored in the cache as CMAKE_C_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_C_COMPILER variable is defined.

NOTE: Options that are required to make the compiler work correctly can be included; they can not be changed.

$ export CC="custom-compiler --arg1 --arg2"

  CFLAGS

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling C files. Will only be used by CMake on the first configuration to determine CC default compilation flags, after which the value for CFLAGS is stored in the cache as CMAKE_C_FLAGS. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_C_FLAGS variable is defined.

See also CMAKE_C_FLAGS_INIT.

  CSFLAGS

New in version 3.9.2.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling CSharp files. Will only be used by CMake on the first configuration to determine CSharp default compilation flags, after which the value for CSFLAGS is stored in the cache as CMAKE_CSharp_FLAGS. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_CSharp_FLAGS variable is defined.

See also CMAKE_CSharp_FLAGS_INIT.

  CUDACXX

New in version 3.8.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling CUDA language files. Will only be used by CMake on the first configuration to determine CUDA compiler, after which the value for CUDA is stored in the cache as CMAKE_CUDA_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_CUDA_COMPILER variable is defined.

NOTE: Options that are required to make the compiler work correctly can be included; they can not be changed.

$ export CUDACXX="custom-compiler --arg1 --arg2"

  CUDAFLAGS

New in version 3.8.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling CUDA files. Will only be used by CMake on the first configuration to determine CUDA default compilation flags, after which the value for CUDAFLAGS is stored in the cache as CMAKE_CUDA_FLAGS. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_CUDA_FLAGS variable is defined.

See also CMAKE_CUDA_FLAGS_INIT.

  CUDAHOSTCXX

New in version 3.8.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling host code when compiling CUDA language files. Will only be used by CMake on the first configuration to determine CUDA host compiler, after which the value for CUDAHOSTCXX is stored in the cache as CMAKE_CUDA_HOST_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_CUDA_HOST_COMPILER variable is defined.

This environment variable is primarily meant for use with projects that enable CUDA as a first-class language. The FindCUDA module will also use it to initialize its CUDA_HOST_COMPILER setting.

  CXX

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling CXX language files. Will only be used by CMake on the first configuration to determine CXX compiler, after which the value for CXX is stored in the cache as CMAKE_CXX_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_CXX_COMPILER variable is defined.

NOTE: Options that are required to make the compiler work correctly can be included; they can not be changed.

$ export CXX="custom-compiler --arg1 --arg2"

  CXXFLAGS

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling CXX (C++) files. Will only be used by CMake on the first configuration to determine CXX default compilation flags, after which the value for CXXFLAGS is stored in the cache as CMAKE_CXX_FLAGS. For any configuration run ( including the first), the environment variable will be ignored if the CMAKE_CXX_FLAGS variable is defined.

See also CMAKE_CXX_FLAGS_INIT.

  FC

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling Fortran language files. Will only be used by CMake on the first configuration to determine Fortran compiler, after which the value for Fortran is stored in the cache as CMAKE_Fortran_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_Fortran_COMPILER variable is defined.

NOTE: Options that are required to make the compiler work correctly can be included; they can not be changed.

$ export FC="custom-compiler --arg1 --arg2"

  FFLAGS

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling Fortran files. Will only be used by CMake on the first configuration to determine Fortran default compilation flags, after which the value for FFLAGS is stored in the cache as CMAKE_Fortran_FLAGS. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_Fortran_FLAGS variable is defined.

See also CMAKE_Fortran_FLAGS_INIT.

  ISPC

New in version 3.19.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling ISPC language files. Will only be used by CMake on the first configuration to determine ISPC compiler, after which the value for ISPC is stored in the cache as CMAKE_ISPC_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_ISPC_COMPILER variable is defined.

  ISPCFLAGS

New in version 3.19.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling ISPC files. Will only be used by CMake on the first configuration to determine ISPC default compilation flags, after which the value for ISPCFLAGS is stored in the cache as CMAKE_ISPC_FLAGS. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_ISPC_FLAGS variable is defined.

See also CMAKE_ISPC_FLAGS_INIT.

  OBJC

New in version 3.16.7.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling OBJC language files. Will only be used by CMake on the first configuration to determine OBJC compiler, after which the value for OBJC is stored in the cache as CMAKE_OBJC_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_OBJC_COMPILER variable is defined.

If OBJC is not defined, the CC environment variable will be checked instead.

  OBJCXX

New in version 3.16.7.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling OBJCXX language files. Will only be used by CMake on the first configuration to determine OBJCXX compiler, after which the value for OBJCXX is stored in the cache as CMAKE_OBJCXX_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_OBJCXX_COMPILER variable is defined.

If OBJCXX is not defined, the CXX environment variable will be checked instead.

  RC

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling resource files. Will only be used by CMake on the first configuration to determine resource compiler, after which the value for RC is stored in the cache as CMAKE_RC_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_RC_COMPILER variable is defined.

NOTE: Options that are required to make the compiler work correctly can be included; they can not be changed.

$ export RC="custom-compiler --arg1 --arg2"

  RCFLAGS

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Default compilation flags to be used when compiling resource files. Will only be used by CMake on the first configuration to determine resource default compilation flags, after which the value for RCFLAGS is stored in the cache as CMAKE_RC_FLAGS. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_RC_FLAGS variable is defined.

See also CMAKE_RC_FLAGS_INIT.

  SWIFTC

New in version 3.15.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Preferred executable for compiling Swift language files. Will only be used by CMake on the first configuration to determine Swift compiler, after which the value for SWIFTC is stored in the cache as CMAKE_Swift_COMPILER. For any configuration run (including the first), the environment variable will be ignored if the CMAKE_Swift_COMPILER variable is defined.

NOTE: Options that are required to make the compiler work correctly can be included; they can not be changed.

$ export SWIFTC="custom-compiler --arg1 --arg2"

ENVIRONMENT VARIABLES FOR CTEST

  CTEST_INTERACTIVE_DEBUG_MODE

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Environment variable that will exist and be set to 1 when a test executed by ctest(1) is run in interactive mode.

  CTEST_OUTPUT_ON_FAILURE

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Boolean environment variable that controls if the output should be logged for failed tests. Set the value to 1, True, or ON to enable output on failure. See ctest(1) for more information on controlling output of failed tests.

  CTEST_PARALLEL_LEVEL

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Specify the number of tests for CTest to run in parallel. See ctest(1) for more information on parallel test execution.

  CTEST_PROGRESS_OUTPUT

New in version 3.13.

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Boolean environment variable that affects how ctest command output reports overall progress. When set to 1, TRUE, ON or anything else that evaluates to boolean true, progress is reported by repeatedly updating the same line. This greatly reduces the overall verbosity, but is only supported when output is sent directly to a terminal. If the environment variable is not set or has a value that evaluates to false, output is reported normally with each test having its own start and end lines logged to the output.

The --progress option to ctest overrides this environment variable if both are given.

  CTEST_USE_LAUNCHERS_DEFAULT

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Initializes the CTEST_USE_LAUNCHERS variable if not already defined.

  DASHBOARD_TEST_FROM_CTEST

This is a CMake Environment Variable. Its initial value is taken from the calling process environment.

Environment variable that will exist when a test executed by ctest(1) is run in non-interactive mode. The value will be equal to CMAKE_VERSION.

ENVIRONMENT VARIABLES FOR THE CMAKE CURSES INTERFACE

  CCMAKE_COLORS

New in version 3.18.

Determines what colors are used by the CMake curses interface, when run on a terminal that supports colors. The syntax follows the same conventions as LS_COLORS; that is, a list of key/value pairs separated by :.

Keys are a single letter corresponding to a CMake cache variable type:

•   s: A STRING.

•   p: A FILEPATH.

•   c: A value which has an associated list of choices.

•   y: A BOOL which has a true-like value (e.g. ON, YES).

•   n: A BOOL which has a false-like value (e.g. OFF, NO).

    Values are an integer number that specifies what color to use. 0 is black (you probably don’t want to use that). Others are determined by your terminal’s color support. Most (color) terminals will support at least 8 or 16 colors. Some will support up to 256 colors. The colors will likely match this chart, although the first 16 colors may match the original CGA color palette. (Many modern terminal emulators also allow their color palette, at least for the first 16 colors, to be configured by the user.)

    Note that fairly minimal checking is done for bad colors (although a value higher than what curses believes your terminal supports will be silently ignored) or bad syntax.

    For example:

    CCMAKE_COLORS='s=39:p=220:c=207:n=196:y=46'

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