Provided by: cmake-data_4.1.1+really3.31.6-2ubuntu1_all 
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 <#
cmake-language-environment-variables> section in the cmake-language manual.
ENVIRONMENT VARIABLES THAT CHANGE BEHAVIOR
CMAKE_APPBUNDLE_PATH
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_APPBUNDLE_PATH environment variable may be set to a list of directories to be searched for
macOS application bundles by the find_program() <#command:find_program> and find_package() <#
command:find_package> commands.
This variable may hold a single directory or a list of directories separated by : on UNIX or ; on Windows
(the same as the PATH environment variable convention on those platforms).
See also the CMAKE_APPBUNDLE_PATH <#variable:CMAKE_APPBUNDLE_PATH> CMake variable.
CMAKE_FRAMEWORK_PATH
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_FRAMEWORK_PATH environment variable may be set to a list of directories to be searched for
macOS frameworks by the find_library() <#command:find_library>, find_package() <#command:find_package>,
find_path() <#command:find_path> and find_file() <#command:find_file> commands.
This variable may hold a single directory or a list of directories separated by : on UNIX or ; on Windows
(the same as the PATH environment variable convention on those platforms).
See also the CMAKE_FRAMEWORK_PATH <#variable:CMAKE_FRAMEWORK_PATH> CMake variable.
CMAKE_INCLUDE_PATH
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_INCLUDE_PATH environment variable may be set to a list of directories to be searched by the
find_file() <#command:find_file> and find_path() <#command:find_path> commands.
This variable may hold a single directory or a list of directories separated by : on UNIX or ; on Windows
(the same as the PATH environment variable convention on those platforms).
See also the CMAKE_INCLUDE_PATH <#variable:CMAKE_INCLUDE_PATH> CMake variable.
CMAKE_LIBRARY_PATH
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_LIBRARY_PATH environment variable may be set to a list of directories to be searched by the
find_library() <#command:find_library> command.
This variable may hold a single directory or a list of directories separated by : on UNIX or ; on Windows
(the same as the PATH environment variable convention on those platforms).
See also the CMAKE_LIBRARY_PATH <#variable:CMAKE_LIBRARY_PATH> CMake variable.
CMAKE_MAXIMUM_RECURSION_DEPTH
Added in version 3.27.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Maximum recursion depth for CMake scripts. This environment variable is used if the
CMAKE_MAXIMUM_RECURSION_DEPTH <#variable:CMAKE_MAXIMUM_RECURSION_DEPTH> variable is not set. See that
variable's documentation for details.
CMAKE_PREFIX_PATH
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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() <#command:find_package>, find_program() <#
command:find_program>, find_library() <#command:find_library>, find_file() <#command:find_file>, and
find_path() <#command: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 <#variable:CMAKE_PREFIX_PATH> CMake variable.
CMAKE_PROGRAM_PATH
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_PROGRAM_PATH environment variable may be set to a list of directories to be searched by the
find_program() <#command:find_program> command.
This variable may hold a single directory or a list of directories separated by : on UNIX or ; on Windows
(the same as the PATH environment variable convention on those platforms).
See also the CMAKE_PROGRAM_PATH <#variable:CMAKE_PROGRAM_PATH> CMake variable.
CMAKE_TLS_VERIFY
Added in version 3.30.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specify the default value for the file(DOWNLOAD) <#download> and file(UPLOAD) <#upload> commands'
TLS_VERIFY option. This environment variable is used if the option is not given and the CMAKE_TLS_VERIFY
<#variable:CMAKE_TLS_VERIFY> cmake variable is not set.
This variable is also used by the ExternalProject <#module:ExternalProject> and FetchContent <#
module:FetchContent> modules for internal calls to file(DOWNLOAD) <#download> and git clone.
CMAKE_TLS_VERSION
Added in version 3.30.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specify the default value for the file(DOWNLOAD) <#download> and file(UPLOAD) <#upload> commands'
TLS_VERSION option. This environment variable is used if the option is not given and the
CMAKE_TLS_VERSION <#variable:CMAKE_TLS_VERSION> cmake variable is not set. See that variable for allowed
values.
This variable is also used by the ExternalProject <#module:ExternalProject> and FetchContent <#
module:FetchContent> modules for internal calls to file(DOWNLOAD) <#download> and git clone.
SSL_CERT_DIR
Added in version 3.25.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specify default directory containing CA certificates. It overrides the default CA directory used.
SSL_CERT_FILE
Added in version 3.25.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specify the file name containing CA certificates. It overrides the default, os-specific CA file used.
ENVIRONMENT VARIABLES THAT CONTROL THE BUILD
ADSP_ROOT
Added in version 3.24.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The ADSP_ROOT environment variable specifies a default value for the CMAKE_ADSP_ROOT <#
variable:CMAKE_ADSP_ROOT> variable when there is no explicit configuration given on the first run while
creating a new build tree.
CMAKE_APPLE_SILICON_PROCESSOR
Added in version 3.19.2.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_HOST_SYSTEM_PROCESSOR>. The value must be either
arm64 or x86_64.
The CMAKE_APPLE_SILICON_PROCESSOR <#variable:CMAKE_APPLE_SILICON_PROCESSOR> normal variable, if set,
overrides this environment variable.
CMAKE_BUILD_PARALLEL_LEVEL
Added in version 3.12.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#build-tool-mode>. For example, if CMAKE_BUILD_PARALLEL_LEVEL is set to 8, the
underlying build tool will execute up to 8 jobs concurrently as if cmake --build were invoked with the
--parallel 8 <#cmdoption-cmake-build-j> option.
If this variable is defined empty the native build tool's default number is used.
CMAKE_BUILD_TYPE
Added in version 3.22.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_BUILD_TYPE environment variable specifies a default value for the CMAKE_BUILD_TYPE <#
variable:CMAKE_BUILD_TYPE> variable when there is no explicit configuration given on the first run while
creating a new build tree.
CMAKE_COLOR_DIAGNOSTICS
Added in version 3.24.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specifies a default value for the CMAKE_COLOR_DIAGNOSTICS <#variable:CMAKE_COLOR_DIAGNOSTICS> variable
when there is no explicit value given on the first run.
CMAKE_CONFIG_DIR
Added in version 3.31.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specify a CMake user-wide configuration directory for cmake-file-api(7) <#manual:cmake-file-api(7)>
queries.
If this environment variable is not set, the default user-wide configuration directory is
platform-specific:
• Windows: %LOCALAPPDATA%\CMake
• macOS: $XDG_CONFIG_HOME/CMake if set, otherwise $HOME/Library/Application Support/CMake
• Linux/Other: $XDG_CONFIG_HOME/cmake if set, otherwise $HOME/.config/cmake
CMAKE_CONFIG_TYPE
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The default build configuration for Build a Project <#build-tool-mode> and ctest build handler when there
is no explicit configuration given.
CMAKE_CONFIGURATION_TYPES
Added in version 3.22.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_CONFIGURATION_TYPES environment variable specifies a default value for the
CMAKE_CONFIGURATION_TYPES <#variable:CMAKE_CONFIGURATION_TYPES> variable when there is no explicit
configuration given on the first run while creating a new build tree.
CMAKE_CROSSCOMPILING_EMULATOR
Added in version 3.28.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The default value for CMAKE_CROSSCOMPILING_EMULATOR <#variable:CMAKE_CROSSCOMPILING_EMULATOR> 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_CROSSCOMPILING_EMULATOR <#
variable:CMAKE_CROSSCOMPILING_EMULATOR>.
CMAKE_EXPORT_BUILD_DATABASE
Added in version 3.31.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The default value for CMAKE_EXPORT_BUILD_DATABASE <#variable:CMAKE_EXPORT_BUILD_DATABASE> 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_BUILD_DATABASE <#
variable:CMAKE_EXPORT_BUILD_DATABASE>.
Note:
This variable is meaningful only when experimental support for build databases has been enabled by the
CMAKE_EXPERIMENTAL_EXPORT_BUILD_DATABASE gate.
CMAKE_EXPORT_COMPILE_COMMANDS
Added in version 3.17.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The default value for CMAKE_EXPORT_COMPILE_COMMANDS <#variable: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 <#
variable:CMAKE_EXPORT_COMPILE_COMMANDS>.
CMAKE_GENERATOR
Added in version 3.15.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specifies the CMake default generator to use when no generator is supplied with -G <#cmdoption-cmake-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:CMAKE_GENERATOR> variable.
Some generators may be additionally configured using the environment variables:
• CMAKE_GENERATOR_PLATFORM <#envvar:CMAKE_GENERATOR_PLATFORM>
• CMAKE_GENERATOR_TOOLSET <#envvar:CMAKE_GENERATOR_TOOLSET>
• CMAKE_GENERATOR_INSTANCE <#envvar:CMAKE_GENERATOR_INSTANCE>
CMAKE_GENERATOR_INSTANCE
Added in version 3.15.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Default value for CMAKE_GENERATOR_INSTANCE <#variable:CMAKE_GENERATOR_INSTANCE> if no Cache entry is
present. This value is only applied if CMAKE_GENERATOR <#envvar:CMAKE_GENERATOR> is set.
CMAKE_GENERATOR_PLATFORM
Added in version 3.15.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Default value for CMAKE_GENERATOR_PLATFORM <#variable:CMAKE_GENERATOR_PLATFORM> if no Cache entry is
present and no value is specified by cmake -A <#cmdoption-cmake-A> option. This value is only applied if
CMAKE_GENERATOR <#envvar:CMAKE_GENERATOR> is set.
CMAKE_GENERATOR_TOOLSET
Added in version 3.15.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Default value for CMAKE_GENERATOR_TOOLSET <#variable:CMAKE_GENERATOR_TOOLSET> if no Cache entry is
present and no value is specified by cmake -T <#cmdoption-cmake-T> option. This value is only applied if
CMAKE_GENERATOR <#envvar:CMAKE_GENERATOR> is set.
CMAKE_INSTALL_MODE
Added in version 3.22.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_INSTALL_MODE environment variable allows users to operate CMake in an alternate mode of
file(INSTALL) <#install> and install() <#command:install>.
The default behavior for an installation is to copy a source file from a source directory into a
destination directory. This environment variable however allows the user to override this behavior,
causing CMake to create symbolic links instead.
Usage Scenarios
Installing symbolic links rather than copying files can help in the following ways:
• Conserving storage space because files do not have to be duplicated on disk.
• Changes to the source of the symbolic link are seen at the install destination without having to re-run
the install step.
• Editing through the link at the install destination will modify the source of the link. This may be
useful when dealing with CMake project hierarchies, i.e. using ExternalProject <#
module:ExternalProject> and consistent source navigation and refactoring is desired across projects.
Allowed Values
The following values are allowed for CMAKE_INSTALL_MODE:
COPY, empty or unset
Duplicate the file at its destination. This is the default behavior.
ABS_SYMLINK
Create an absolute symbolic link to the source file at the destination. Halt with an error if the
link cannot be created.
ABS_SYMLINK_OR_COPY
Like ABS_SYMLINK but fall back to silently copying if the symlink couldn't be created.
REL_SYMLINK
Create a relative symbolic link to the source file at the destination. Halt with an error if the
link cannot be created.
REL_SYMLINK_OR_COPY
Like REL_SYMLINK but fall back to silently copying if the symlink couldn't be created.
SYMLINK
Try as if through REL_SYMLINK and fall back to ABS_SYMLINK if the referenced file cannot be
expressed using a relative path. Halt with an error if the link cannot be created.
SYMLINK_OR_COPY
Like SYMLINK but fall back to silently copying if the symlink couldn't be created.
Note:
A symbolic link consists of a reference file path rather than contents of its own, hence there are two
ways to express the relation, either by a relative or an absolute path.
When To Set The Environment Variable
For the environment variable to take effect, it must be set during the correct build phase(s).
• If the project calls file(INSTALL) <#install> directly, the environment variable must be set during the
configuration phase.
• In order to apply to install() <#command:install>, the environment variable must be set during
installation. This could be during a build if using the install or package build targets, or separate
from the build when invoking an install or running cpack <#manual:cpack(1)> from the command line.
• When using ExternalProject <#module:ExternalProject>, it might be required during the build phase,
since the external project's own configure, build and install steps will execute during the main
project's build phase.
Given the above, it is recommended to set the environment variable consistently across all phases
(configure, build and install).
Caveats
Use this environment variable with caution. The following highlights some points to be considered:
• CMAKE_INSTALL_MODE only affects files, not directories.
• Symbolic links are not available on all platforms.
• The way this environment variable interacts with the install step of ExternalProject <#
module:ExternalProject> is more complex. For further details, see that module's documentation.
• A symbolic link ties the destination to the source in a persistent way. Writing to either of the two
affects both file system objects. This is in contrast to normal install behavior which only copies
files as they were at the time the install was performed, with no enduring relationship between the
source and destination of the install.
• Combining CMAKE_INSTALL_MODE with IOS_INSTALL_COMBINED <#prop_tgt:IOS_INSTALL_COMBINED> is not
supported.
• Changing CMAKE_INSTALL_MODE from what it was on a previous run can lead to unexpected results. Moving
from a non-symlinking mode to a symlinking mode will discard any previous file at the destination, but
the reverse is not true. Once a symlink exists at the destination, even if you switch to a non-symlink
mode, the symlink will continue to exist at the destination and will not be replaced by an actual file.
CMAKE_INSTALL_PARALLEL_LEVEL
Added in version 3.31.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specifies the default maximum number of concurrent processes to use when installing using cmake
--install.
This has no impact unless INSTALL_PARALLEL <#prop_gbl:INSTALL_PARALLEL> is enabled.
CMAKE_INSTALL_PREFIX
Added in version 3.29.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_INSTALL_PREFIX environment variable specifies a custom default value for the
CMAKE_INSTALL_PREFIX <#variable:CMAKE_INSTALL_PREFIX> variable in place of the default values specified
by CMake itself. The value specified must be an absolute path to a directory.
CMAKE_<LANG>_COMPILER_LAUNCHER
Added in version 3.17.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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:CMAKE_<LANG>_COMPILER_LAUNCHER> variable is
defined.
CMAKE_<LANG>_IMPLICIT_LINK_DIRECTORIES_EXCLUDE
Added in version 3.27.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
A semicolon-separated list <#cmake-language-lists> of directories to exclude from the
CMAKE_<LANG>_IMPLICIT_LINK_DIRECTORIES <#variable:CMAKE_<LANG>_IMPLICIT_LINK_DIRECTORIES> variable when
it is automatically detected from the <LANG> compiler.
This may be used to work around misconfigured compiler drivers that pass extraneous implicit link
directories to their linker.
CMAKE_<LANG>_LINKER_LAUNCHER
Added in version 3.21.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Default launcher to use when linking a target of 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>_LINKER_LAUNCHER <#
variable:CMAKE_<LANG>_LINKER_LAUNCHER> variable is defined.
CMAKE_MSVCIDE_RUN_PATH
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Extra PATH locations for custom commands when using Visual Studio Generators <#visual-studio-generators>.
The CMAKE_MSVCIDE_RUN_PATH environment variable sets the default value for the CMAKE_MSVCIDE_RUN_PATH <#
variable:CMAKE_MSVCIDE_RUN_PATH> variable if not already explicitly set.
CMAKE_NO_VERBOSE
Added in version 3.14.
Disables verbose output from CMake when VERBOSE <#envvar: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 <#cmake-language-environment-variables>. 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:CMAKE_OSX_ARCHITECTURES> variable. See OSX_ARCHITECTURES <#prop_tgt:OSX_ARCHITECTURES> for
more information.
CMAKE_TEST_LAUNCHER
Added in version 3.29.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The default value for the CMAKE_TEST_LAUNCHER <#variable:CMAKE_TEST_LAUNCHER> variable 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_TEST_LAUNCHER <#
variable:CMAKE_TEST_LAUNCHER>.
CMAKE_TOOLCHAIN_FILE
Added in version 3.21.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
The CMAKE_TOOLCHAIN_FILE environment variable specifies a default value for the CMAKE_TOOLCHAIN_FILE <#
variable:CMAKE_TOOLCHAIN_FILE> variable 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_TOOLCHAIN_FILE <#variable:CMAKE_TOOLCHAIN_FILE>.
DESTDIR
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 packagers to install software in a staging directory.
For example, running
make DESTDIR=/package/stage install
will install the software using the installation prefix, e.g. /usr/local, prepended with the DESTDIR
value which gives /package/stage/usr/local. The packaging tool may then construct the package from the
content of the /package/stage directory.
See the CMAKE_INSTALL_PREFIX <#variable:CMAKE_INSTALL_PREFIX> variable to control the installation prefix
when configuring a build tree. Or, when using the cmake(1) <#manual:cmake(1)> command-line tool's
--install <#cmdoption-cmake-install> mode, one may specify a different prefix using the --prefix <#
cmdoption-cmake--install-0> option.
Note:
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 <#cmake-language-environment-variables>. 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 <#
variable:CMAKE_EXE_LINKER_FLAGS_INIT>, CMAKE_SHARED_LINKER_FLAGS_INIT <#
variable:CMAKE_SHARED_LINKER_FLAGS_INIT>, and CMAKE_MODULE_LINKER_FLAGS_INIT <#
variable: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 <#cmake-language-environment-variables>. 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:CMAKE_OSX_DEPLOYMENT_TARGET> variable.
<PackageName>_ROOT
Added in version 3.12.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Calls to find_package(<PackageName>) <#command:find_package> will search in prefixes specified by the
<PackageName>_ROOT environment variable, where <PackageName> is the (case-preserved) name given to the
find_package() <#command: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 <#
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 <#variable:<PackageName>_ROOT> CMake variable.
<PACKAGENAME>_ROOT
Added in version 3.27.
Calls to find_package(<PackageName>) <#command:find_package> will also search in prefixes
specified by the upper-case <PACKAGENAME>_ROOT environment variable. See policy CMP0144 <#
policy:CMP0144>.
Note:
Note that the <PackageName>_ROOT and <PACKAGENAME>_ROOT environment variables are distinct only on
platforms that have case-sensitive environments.
VERBOSE
Added 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 <#build-tool-mode> and CMAKE_NO_VERBOSE <#envvar:CMAKE_NO_VERBOSE> environment
variable
ENVIRONMENT VARIABLES FOR LANGUAGES
ASM<DIALECT>
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 one
of:
• ASM
• ASM_NASM (Netwide Assembler)
• ASM_MASM (Microsoft Assembler)
• ASM_MARMASM (Microsoft ARM Assembler)
• 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 <#
variable:CMAKE_<LANG>_COMPILER>. For subsequent configuration runs, the environment variable will be
ignored in favor of CMAKE_ASM<DIALECT>_COMPILER <#variable:CMAKE_<LANG>_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 <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling a specific dialect of an assembly language.
ASM<DIALECT>FLAGS can be one of:
• ASMFLAGS
• ASM_NASMFLAGS
• ASM_MASMFLAGS
• ASM_MARMASMFLAGS
• ASM-ATTFLAGS
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_ASM<DIALECT>_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache
entry. This occurs the first time a build tree is configured for language ASM<DIALECT>. For any
configuration run (including the first), the environment variable will be ignored if the
CMAKE_ASM<DIALECT>_FLAGS <#variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_ASM<DIALECT>_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
CC
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first), the
environment variable will be ignored if the CMAKE_C_COMPILER <#variable:CMAKE_<LANG>_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 <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling C files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_C_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry. This
occurs the first time a build tree is configured for language C. For any configuration run (including
the first), the environment variable will be ignored if the CMAKE_C_FLAGS <#variable:CMAKE_<LANG>_FLAGS>
variable is already defined.
See also CMAKE_C_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
CSFLAGS
Added in version 3.9.2.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling CSharp files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_CSharp_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry.
This occurs the first time a build tree is configured for language CSharp. For any configuration run
(including the first), the environment variable will be ignored if the CMAKE_CSharp_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_CSharp_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
CUDAARCHS
Added in version 3.20.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Value used to initialize CMAKE_CUDA_ARCHITECTURES <#variable:CMAKE_CUDA_ARCHITECTURES> on the first
configuration. Subsequent runs will use the value stored in the cache.
This is a semicolon-separated list of architectures as described in CUDA_ARCHITECTURES <#
prop_tgt:CUDA_ARCHITECTURES>.
CUDACXX
Added in version 3.8.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first),
the environment variable will be ignored if the CMAKE_CUDA_COMPILER <#variable:CMAKE_<LANG>_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
Added in version 3.8.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling CUDA files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_CUDA_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry. This
occurs the first time a build tree is configured for language CUDA. For any configuration run (including
the first), the environment variable will be ignored if the CMAKE_CUDA_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_CUDA_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
CUDAHOSTCXX
Added in version 3.8.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_HOST_COMPILER>. This
environment variable is preferred over CMAKE_CUDA_HOST_COMPILER <#variable:CMAKE_<LANG>_HOST_COMPILER>.
This environment variable is primarily meant for use with projects that enable CUDA as a first-class
language.
Note:
Ignored when using Visual Studio Generators <#visual-studio-generators>.
Added in version 3.13: The FindCUDA <#module:FindCUDA> module will use this variable to initialize its
CUDA_HOST_COMPILER setting.
CXX
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first),
the environment variable will be ignored if the CMAKE_CXX_COMPILER <#variable:CMAKE_<LANG>_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 <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling CXX (C++) files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_CXX_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry. This
occurs the first time a build tree is configured for language CXX. For any configuration run (including
the first), the environment variable will be ignored if the CMAKE_CXX_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_CXX_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
FC
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the
first), the environment variable will be ignored if the CMAKE_Fortran_COMPILER <#
variable:CMAKE_<LANG>_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 <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling Fortran files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_Fortran_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry.
This occurs the first time a build tree is configured for language Fortran. For any configuration run
(including the first), the environment variable will be ignored if the CMAKE_Fortran_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_Fortran_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
HIPCXX
Added in version 3.21.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Preferred executable for compiling HIP language files. Will only be used by CMake on the first
configuration to determine HIP compiler, after which the value for HIP is stored in the cache as
CMAKE_HIP_COMPILER <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first),
the environment variable will be ignored if the CMAKE_HIP_COMPILER <#variable:CMAKE_<LANG>_COMPILER>
variable is defined.
HIPFLAGS
Added in version 3.21.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling HIP files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_HIP_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry. This
occurs the first time a build tree is configured for language HIP. For any configuration run (including
the first), the environment variable will be ignored if the CMAKE_HIP_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_HIP_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
HIPHOSTCXX
Added in version 3.28.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Preferred executable for compiling host code when compiling HIP language files with the NVIDIA CUDA
Compiler. Will only be used by CMake on the first configuration to determine HIP host compiler, after
which the value for HIPHOSTCXX is stored in the cache as CMAKE_HIP_HOST_COMPILER <#
variable:CMAKE_<LANG>_HOST_COMPILER>.
This environment variable is primarily meant for use with projects that enable HIP as a first-class
language.
Note:
Ignored when using Visual Studio Generators <#visual-studio-generators>.
ISPC
Added in version 3.19.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first),
the environment variable will be ignored if the CMAKE_ISPC_COMPILER <#variable:CMAKE_<LANG>_COMPILER>
variable is defined.
ISPCFLAGS
Added in version 3.19.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling ISPC files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_ISPC_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry. This
occurs the first time a build tree is configured for language ISPC. For any configuration run (including
the first), the environment variable will be ignored if the CMAKE_ISPC_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_ISPC_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
OBJC
Added in version 3.16.7.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first),
the environment variable will be ignored if the CMAKE_OBJC_COMPILER <#variable:CMAKE_<LANG>_COMPILER>
variable is defined.
If OBJC is not defined, the CC <#envvar:CC> environment variable will be checked instead.
OBJCFLAGS
Added in version 3.16.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling Objective C files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_OBJC_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry. This
occurs the first time a build tree is configured for language OBJC. For any configuration run (including
the first), the environment variable will be ignored if the CMAKE_OBJC_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_OBJC_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
OBJCXX
Added in version 3.16.7.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first),
the environment variable will be ignored if the CMAKE_OBJCXX_COMPILER <#variable:CMAKE_<LANG>_COMPILER>
variable is defined.
If OBJCXX is not defined, the CXX <#envvar:CXX> environment variable will be checked instead.
OBJCXXFLAGS
Added in version 3.16.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling Objective C++ (.mm) files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_OBJCXX_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry.
This occurs the first time a build tree is configured for language OBJCXX. For any configuration run
(including the first), the environment variable will be ignored if the CMAKE_OBJCXX_FLAGS <#
variable:CMAKE_<LANG>_FLAGS> variable is already defined.
See also CMAKE_OBJCXX_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
RC
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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
<#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first), the environment
variable will be ignored if the CMAKE_RC_COMPILER <#variable:CMAKE_<LANG>_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 <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Add default compilation flags to be used when compiling RC (resource) files.
CMake uses this environment variable value, in combination with its own builtin default flags for the
toolchain, to initialize and store the CMAKE_RC_FLAGS <#variable:CMAKE_<LANG>_FLAGS> cache entry. This
occurs the first time a build tree is configured for language RC. For any configuration run (including
the first), the environment variable will be ignored if the CMAKE_RC_FLAGS <#variable:CMAKE_<LANG>_FLAGS>
variable is already defined.
See also CMAKE_RC_FLAGS_INIT <#variable:CMAKE_<LANG>_FLAGS_INIT>.
SWIFTC
Added in version 3.15.
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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 <#variable:CMAKE_<LANG>_COMPILER>. For any configuration run (including the first),
the environment variable will be ignored if the CMAKE_Swift_COMPILER <#variable:CMAKE_<LANG>_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 <#cmake-language-environment-variables>. 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) <#manual:ctest(1)>
is run in interactive mode.
CTEST_NO_TESTS_ACTION
Added in version 3.26.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Environment variable that controls how ctest <#manual:ctest(1)> handles cases when there are no tests to
run. Possible values are: error, ignore, empty or unset.
The --no-tests=<action> <#cmdoption-ctest-no-tests> option to ctest <#manual:ctest(1)> overrides this
environment variable if both are given.
CTEST_OUTPUT_ON_FAILURE
This is a CMake Environment Variable <#cmake-language-environment-variables>. 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) <#manual:ctest(1)> for more information on
controlling output of failed tests.
CTEST_PARALLEL_LEVEL
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Specify the number of tests for CTest to run in parallel. For example, if CTEST_PARALLEL_LEVEL is set to
8, CTest will run up to 8 tests concurrently as if ctest were invoked with the --parallel 8 <#
cmdoption-ctest-j> option.
Changed in version 3.29: The value may be empty, or 0, to let ctest use a default level of parallelism,
or unbounded parallelism, respectively, as documented by the ctest --parallel <#cmdoption-ctest-j>
option.
On Windows, environment variables cannot be set to an empty string. CTest will interpret a
whitespace-only string as empty.
In CMake 3.28 and earlier, an empty or 0 value was equivalent to 1.
See ctest(1) <#manual:ctest(1)> for more information on parallel test execution.
CTEST_PROGRESS_OUTPUT
Added in version 3.13.
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Boolean environment variable that affects how ctest <#manual:ctest(1)> 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 <#cmdoption-ctest-progress> option to ctest <#manual:ctest(1)> overrides this environment
variable if both are given.
CTEST_USE_LAUNCHERS_DEFAULT
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Initializes the CTEST_USE_LAUNCHERS <#variable:CTEST_USE_LAUNCHERS> variable if not already defined.
DASHBOARD_TEST_FROM_CTEST
This is a CMake Environment Variable <#cmake-language-environment-variables>. Its initial value is taken
from the calling process environment.
Environment variable that will exist when a test executed by ctest(1) <#manual:ctest(1)> is run in
non-interactive mode. The value will be equal to CMAKE_VERSION <#variable:CMAKE_VERSION>.
ENVIRONMENT VARIABLES FOR THE CMAKE CURSES INTERFACE
CCMAKE_COLORS
Added 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
<https://upload.wikimedia.org/wikipedia/commons/1/15/Xterm_256color_chart.svg>, although the first 16
colors may match the original CGA color palette <https://en.wikipedia.org/wiki/Color_Graphics_Adapter#
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'
Copyright
2000-2024 Kitware, Inc. and Contributors
3.31.6 December 01, 2025 CMAKE-ENV-VARIABLES(7)