CMake/Help/manual/cmake-policies.7.rst
2025-03-05 17:11:56 +01:00

546 lines
24 KiB
ReStructuredText

.. cmake-manual-description: CMake Policies Reference
cmake-policies(7)
*****************
.. only:: html
.. contents::
Introduction
============
CMake policies introduce behavior changes while preserving compatibility
for existing project releases. Policies are deprecation mechanisms, not
feature toggles. Each policy documents a deprecated ``OLD`` behavior and
a preferred ``NEW`` behavior. Projects must be updated over time to
use the ``NEW`` behavior, but their existing releases will continue to
work with the ``OLD`` behavior.
Updating Projects
-----------------
When policies are newly introduced by a version of CMake, their ``OLD``
behaviors are immediately deprecated by that version of CMake and later.
Projects should be updated to use the ``NEW`` behaviors of the policies
as soon as possible.
Use the :command:`cmake_minimum_required` command to record the latest
version of CMake for which a project has been updated.
For example:
..
Sync this cmake_minimum_required example with ``Help/dev/maint.rst``.
.. code-block:: cmake
cmake_minimum_required(VERSION 3.10...4.0)
This uses the ``<min>...<max>`` syntax to enable the ``NEW`` behaviors
of policies introduced in CMake 4.0 and earlier while only requiring a
minimum version of CMake 3.10. The project is expected to work with
both the ``OLD`` and ``NEW`` behaviors of policies introduced between
those versions.
Transition Schedule
-------------------
To help projects port to the ``NEW`` behaviors of policies on their own
schedule, CMake offers a transition period:
* If a policy is not set by a project, CMake uses its ``OLD`` behavior,
but may warn that the policy has not been set.
* Users running CMake may silence the warning without modifying a
project by setting the :variable:`CMAKE_POLICY_DEFAULT_CMP<NNNN>`
variable as a cache entry on the :manual:`cmake(1)` command line:
.. code-block:: shell
cmake -DCMAKE_POLICY_DEFAULT_CMP0990=OLD ...
* Projects may silence the warning by using the :command:`cmake_policy`
command to explicitly set the policy to ``OLD`` or ``NEW`` behavior:
.. code-block:: cmake
if(POLICY CMP0990)
cmake_policy(SET CMP0990 NEW)
endif()
.. note::
A policy should almost never be set to ``OLD``, except to silence
warnings in an otherwise frozen or stable codebase, or temporarily
as part of a larger migration path.
* If a policy is set to ``OLD`` by a project, CMake versions released
at least |POLICY_OLD_DELAY_WARNING| after the version that introduced
a policy may issue a warning that the policy's ``OLD`` behavior will
be removed from a future version of CMake.
* If a policy is not set to ``NEW`` by a project, CMake versions released
at least |POLICY_OLD_DELAY_ERROR| after the version that introduced a
policy, and whose major version number is higher, may issue an error
that the policy's ``OLD`` behavior has been removed.
.. |POLICY_OLD_DELAY_WARNING| replace:: 2 years
.. |POLICY_OLD_DELAY_ERROR| replace:: 6 years
Supported Policies
==================
The following policies are supported.
Policies Introduced by CMake 4.1
--------------------------------
.. toctree::
:maxdepth: 1
CMP0190: FindPython enforce consistency in cross-compiling mode. </policy/CMP0190>
CMP0189: TARGET_PROPERTY evaluates LINK_LIBRARIES properties transitively. </policy/CMP0189>
CMP0188: The FindGCCXML module is removed. </policy/CMP0188>
CMP0187: Include source file without an extension after the same name with an extension. </policy/CMP0187>
CMP0186: Regular expressions match ^ at most once in repeated searches. </policy/CMP0186>
Policies Introduced by CMake 4.0
--------------------------------
.. toctree::
:maxdepth: 1
CMP0185: FindRuby no longer provides upper-case RUBY_* variables. </policy/CMP0185>
CMP0184: MSVC runtime checks flags are selected by an abstraction. </policy/CMP0184>
CMP0183: add_feature_info() supports full Condition Syntax. </policy/CMP0183>
CMP0182: Create shared library archives by default on AIX. </policy/CMP0182>
CMP0181: Link command-line fragment variables are parsed and re-quoted. </policy/CMP0181>
Policies Introduced by CMake 3.31
---------------------------------
.. toctree::
:maxdepth: 1
CMP0180: project() always sets <PROJECT-NAME>_* as normal variables. </policy/CMP0180>
CMP0179: De-duplication of static libraries on link lines keeps first occurrence. </policy/CMP0179>
CMP0178: Test command lines preserve empty arguments. </policy/CMP0178>
CMP0177: install() DESTINATION paths are normalized. </policy/CMP0177>
CMP0176: execute_process() ENCODING is UTF-8 by default. </policy/CMP0176>
CMP0175: add_custom_command() rejects invalid arguments. </policy/CMP0175>
CMP0174: cmake_parse_arguments(PARSE_ARGV) defines a variable for an empty string after a single-value keyword. </policy/CMP0174>
CMP0173: The CMakeFindFrameworks module is removed. </policy/CMP0173>
CMP0172: The CPack module enables per-machine installation by default in the CPack WIX Generator. </policy/CMP0172>
CMP0171: 'codegen' is a reserved target name. </policy/CMP0171>
Policies Introduced by CMake 3.30
---------------------------------
.. toctree::
:maxdepth: 1
CMP0170: FETCHCONTENT_FULLY_DISCONNECTED requirements are enforced. </policy/CMP0170>
CMP0169: FetchContent_Populate(depName) single-argument signature is deprecated. </policy/CMP0169>
CMP0168: FetchContent implements steps directly instead of through a sub-build. </policy/CMP0168>
CMP0167: The FindBoost module is removed. </policy/CMP0167>
CMP0166: TARGET_PROPERTY evaluates link properties transitively over private dependencies of static libraries. </policy/CMP0166>
CMP0165: enable_language() must not be called before project(). </policy/CMP0165>
CMP0164: add_library() rejects SHARED libraries when not supported by the platform. </policy/CMP0164>
CMP0163: The GENERATED source file property is now visible in all directories. </policy/CMP0163>
CMP0162: Visual Studio generators add UseDebugLibraries indicators by default. </policy/CMP0162>
Policies Introduced by CMake 3.29
---------------------------------
.. toctree::
:maxdepth: 1
CMP0161: CPACK_PRODUCTBUILD_DOMAINS defaults to true. </policy/CMP0161>
CMP0160: More read-only target properties now error when trying to set them. </policy/CMP0160>
CMP0159: file(STRINGS) with REGEX updates CMAKE_MATCH_<n>. </policy/CMP0159>
CMP0158: add_test() honors CMAKE_CROSSCOMPILING_EMULATOR only when cross-compiling. </policy/CMP0158>
CMP0157: Swift compilation mode is selected by an abstraction. </policy/CMP0157>
CMP0156: De-duplicate libraries on link lines based on linker capabilities. </policy/CMP0156>
Policies Introduced by CMake 3.28
---------------------------------
.. toctree::
:maxdepth: 1
CMP0155: C++ sources in targets with at least C++20 are scanned for imports when supported. </policy/CMP0155>
CMP0154: Generated files are private by default in targets using file sets. </policy/CMP0154>
CMP0153: The exec_program command should not be called. </policy/CMP0153>
CMP0152: file(REAL_PATH) resolves symlinks before collapsing ../ components. </policy/CMP0152>
Policies Introduced by CMake 3.27
---------------------------------
.. toctree::
:maxdepth: 1
CMP0151: AUTOMOC include directory is a system include directory by default. </policy/CMP0151>
CMP0150: ExternalProject_Add and FetchContent_Declare treat relative git repository paths as being relative to parent project's remote. </policy/CMP0150>
CMP0149: Visual Studio generators select latest Windows SDK by default. </policy/CMP0149>
CMP0148: The FindPythonInterp and FindPythonLibs modules are removed. </policy/CMP0148>
CMP0147: Visual Studio generators build custom commands in parallel. </policy/CMP0147>
CMP0146: The FindCUDA module is removed. </policy/CMP0146>
CMP0145: The Dart and FindDart modules are removed. </policy/CMP0145>
CMP0144: find_package uses upper-case PACKAGENAME_ROOT variables. </policy/CMP0144>
Policies Introduced by CMake 3.26
---------------------------------
.. toctree::
:maxdepth: 1
CMP0143: USE_FOLDERS global property is treated as ON by default. </policy/CMP0143>
Policies Introduced by CMake 3.25
---------------------------------
.. toctree::
:maxdepth: 1
CMP0142: The Xcode generator does not append per-config suffixes to library search paths. </policy/CMP0142>
CMP0141: MSVC debug information format flags are selected by an abstraction. </policy/CMP0141>
CMP0140: The return() command checks its arguments. </policy/CMP0140>
Policies Introduced by CMake 3.24
---------------------------------
.. toctree::
:maxdepth: 1
CMP0139: The if() command supports path comparisons using PATH_EQUAL operator. </policy/CMP0139>
CMP0138: CheckIPOSupported uses flags from calling project. </policy/CMP0138>
CMP0137: try_compile() passes platform variables in project mode. </policy/CMP0137>
CMP0136: Watcom runtime library flags are selected by an abstraction. </policy/CMP0136>
CMP0135: ExternalProject and FetchContent ignore timestamps in archives by default for the URL download method. </policy/CMP0135>
CMP0134: Fallback to "HOST" Windows registry view when "TARGET" view is not usable. </policy/CMP0134>
CMP0133: The CPack module disables SLA by default in the CPack DragNDrop Generator. </policy/CMP0133>
CMP0132: Do not set compiler environment variables on first run. </policy/CMP0132>
CMP0131: LINK_LIBRARIES supports the LINK_ONLY generator expression. </policy/CMP0131>
CMP0130: while() diagnoses condition evaluation errors. </policy/CMP0130>
Policies Introduced by CMake 3.23
---------------------------------
.. toctree::
:maxdepth: 1
CMP0129: Compiler id for MCST LCC compilers is now LCC, not GNU. </policy/CMP0129>
Policies Introduced by CMake 3.22
---------------------------------
.. toctree::
:maxdepth: 1
CMP0128: Selection of language standard and extension flags improved. </policy/CMP0128>
CMP0127: cmake_dependent_option() supports full Condition Syntax. </policy/CMP0127>
Policies Introduced by CMake 3.21
---------------------------------
.. toctree::
:maxdepth: 1
CMP0126: set(CACHE) does not remove a normal variable of the same name. </policy/CMP0126>
CMP0125: find_(path|file|library|program) have consistent behavior for cache variables. </policy/CMP0125>
CMP0124: foreach() loop variables are only available in the loop scope. </policy/CMP0124>
CMP0123: ARMClang cpu/arch compile and link flags must be set explicitly. </policy/CMP0123>
CMP0122: UseSWIG use standard library name conventions for csharp language. </policy/CMP0122>
CMP0121: The list command detects invalid indices. </policy/CMP0121>
Policies Introduced by CMake 3.20
---------------------------------
.. toctree::
:maxdepth: 1
CMP0120: The WriteCompilerDetectionHeader module is removed. </policy/CMP0120>
CMP0119: LANGUAGE source file property explicitly compiles as language. </policy/CMP0119>
CMP0118: GENERATED sources may be used across directories without manual marking. </policy/CMP0118>
CMP0117: MSVC RTTI flag /GR is not added to CMAKE_CXX_FLAGS by default. </policy/CMP0117>
CMP0116: Ninja generators transform DEPFILEs from add_custom_command(). </policy/CMP0116>
CMP0115: Source file extensions must be explicit. </policy/CMP0115>
Policies Introduced by CMake 3.19
---------------------------------
.. toctree::
:maxdepth: 1
CMP0114: ExternalProject step targets fully adopt their steps. </policy/CMP0114>
CMP0113: Makefile generators do not repeat custom commands from target dependencies. </policy/CMP0113>
CMP0112: Target file component generator expressions do not add target dependencies. </policy/CMP0112>
CMP0111: An imported target missing its location property fails during generation. </policy/CMP0111>
CMP0110: add_test() supports arbitrary characters in test names. </policy/CMP0110>
CMP0109: find_program() requires permission to execute but not to read. </policy/CMP0109>
Policies Introduced by CMake 3.18
---------------------------------
.. toctree::
:maxdepth: 1
CMP0108: A target cannot link to itself through an alias. </policy/CMP0108>
CMP0107: An ALIAS target cannot overwrite another target. </policy/CMP0107>
CMP0106: The Documentation module is removed. </policy/CMP0106>
CMP0105: Device link step uses the link options. </policy/CMP0105>
CMP0104: CMAKE_CUDA_ARCHITECTURES now detected for NVCC, empty CUDA_ARCHITECTURES not allowed. </policy/CMP0104>
CMP0103: Multiple export() with same FILE without APPEND is not allowed. </policy/CMP0103>
Policies Introduced by CMake 3.17
---------------------------------
.. toctree::
:maxdepth: 1
CMP0102: mark_as_advanced() does nothing if a cache entry does not exist. </policy/CMP0102>
CMP0101: target_compile_options honors BEFORE keyword in all scopes. </policy/CMP0101>
CMP0100: Let AUTOMOC and AUTOUIC process .hh header files. </policy/CMP0100>
CMP0099: Link properties are transitive over private dependencies of static libraries. </policy/CMP0099>
CMP0098: FindFLEX runs flex in CMAKE_CURRENT_BINARY_DIR when executing. </policy/CMP0098>
Policies Introduced by CMake 3.16
---------------------------------
.. toctree::
:maxdepth: 1
CMP0097: ExternalProject_Add with GIT_SUBMODULES "" initializes no submodules. </policy/CMP0097>
CMP0096: project() preserves leading zeros in version components. </policy/CMP0096>
CMP0095: RPATH entries are properly escaped in the intermediary CMake install script. </policy/CMP0095>
Policies Introduced by CMake 3.15
---------------------------------
.. toctree::
:maxdepth: 1
CMP0094: FindPython3, FindPython2 and FindPython use LOCATION for lookup strategy. </policy/CMP0094>
CMP0093: FindBoost reports Boost_VERSION in x.y.z format. </policy/CMP0093>
CMP0092: MSVC warning flags are not in CMAKE_{C,CXX}_FLAGS by default. </policy/CMP0092>
CMP0091: MSVC runtime library flags are selected by an abstraction. </policy/CMP0091>
CMP0090: export(PACKAGE) does not populate package registry by default. </policy/CMP0090>
CMP0089: Compiler id for IBM Clang-based XL compilers is now XLClang. </policy/CMP0089>
Policies Introduced by CMake 3.14
---------------------------------
.. toctree::
:maxdepth: 1
CMP0088: FindBISON runs bison in CMAKE_CURRENT_BINARY_DIR when executing. </policy/CMP0088>
CMP0087: install(SCRIPT | CODE) supports generator expressions. </policy/CMP0087>
CMP0086: UseSWIG honors SWIG_MODULE_NAME via -module flag. </policy/CMP0086>
CMP0085: IN_LIST generator expression handles empty list items. </policy/CMP0085>
CMP0084: The FindQt module does not exist for find_package(). </policy/CMP0084>
CMP0083: Add PIE options when linking executable. </policy/CMP0083>
CMP0082: Install rules from add_subdirectory() are interleaved with those in caller. </policy/CMP0082>
Policies Introduced by CMake 3.13
---------------------------------
.. toctree::
:maxdepth: 1
CMP0081: Relative paths not allowed in LINK_DIRECTORIES target property. </policy/CMP0081>
CMP0080: BundleUtilities cannot be included at configure time. </policy/CMP0080>
CMP0079: target_link_libraries allows use with targets in other directories. </policy/CMP0079>
CMP0078: UseSWIG generates standard target names. </policy/CMP0078>
CMP0077: option() honors normal variables. </policy/CMP0077>
CMP0076: target_sources() command converts relative paths to absolute. </policy/CMP0076>
Policies Introduced by CMake 3.12
---------------------------------
.. toctree::
:maxdepth: 1
CMP0075: Include file check macros honor CMAKE_REQUIRED_LIBRARIES. </policy/CMP0075>
CMP0074: find_package uses PackageName_ROOT variables. </policy/CMP0074>
CMP0073: Do not produce legacy _LIB_DEPENDS cache entries. </policy/CMP0073>
Policies Introduced by CMake 3.11
---------------------------------
.. toctree::
:maxdepth: 1
CMP0072: FindOpenGL prefers GLVND by default when available. </policy/CMP0072>
Policies Introduced by CMake 3.10
---------------------------------
.. toctree::
:maxdepth: 1
CMP0071: Let AUTOMOC and AUTOUIC process GENERATED files. </policy/CMP0071>
CMP0070: Define file(GENERATE) behavior for relative paths. </policy/CMP0070>
Policies Introduced by CMake 3.9
--------------------------------
.. toctree::
:maxdepth: 1
CMP0069: INTERPROCEDURAL_OPTIMIZATION is enforced when enabled. </policy/CMP0069>
CMP0068: RPATH settings on macOS do not affect install_name. </policy/CMP0068>
Policies Introduced by CMake 3.8
--------------------------------
.. toctree::
:maxdepth: 1
CMP0067: Honor language standard in try_compile() source-file signature. </policy/CMP0067>
Policies Introduced by CMake 3.7
--------------------------------
.. toctree::
:maxdepth: 1
CMP0066: Honor per-config flags in try_compile() source-file signature. </policy/CMP0066>
Unsupported Policies
====================
The following policies are no longer supported.
Projects' calls to :command:`cmake_minimum_required(VERSION)` or
:command:`cmake_policy(VERSION)` must set them to ``NEW``.
Their ``OLD`` behaviors have been removed from CMake.
.. _`Policies Introduced by CMake 3.4`:
Policies Introduced by CMake 3.4, Removed by CMake 4.0
------------------------------------------------------
.. toctree::
:maxdepth: 1
CMP0065: Do not add flags to export symbols from executables without the ENABLE_EXPORTS target property. </policy/CMP0065>
CMP0064: Support new TEST if() operator. </policy/CMP0064>
.. _`Policies Introduced by CMake 3.3`:
Policies Introduced by CMake 3.3, Removed by CMake 4.0
------------------------------------------------------
.. toctree::
:maxdepth: 1
CMP0063: Honor visibility properties for all target types. </policy/CMP0063>
CMP0062: Disallow install() of export() result. </policy/CMP0062>
CMP0061: CTest does not by default tell make to ignore errors (-i). </policy/CMP0061>
CMP0060: Link libraries by full path even in implicit directories. </policy/CMP0060>
CMP0059: Do not treat DEFINITIONS as a built-in directory property. </policy/CMP0059>
CMP0058: Ninja requires custom command byproducts to be explicit. </policy/CMP0058>
CMP0057: Support new IN_LIST if() operator. </policy/CMP0057>
.. _`Policies Introduced by CMake 3.2`:
Policies Introduced by CMake 3.2, Removed by CMake 4.0
------------------------------------------------------
.. toctree::
:maxdepth: 1
CMP0056: Honor link flags in try_compile() source-file signature. </policy/CMP0056>
CMP0055: Strict checking for break() command. </policy/CMP0055>
.. _`Policies Introduced by CMake 3.1`:
Policies Introduced by CMake 3.1, Removed by CMake 4.0
------------------------------------------------------
.. toctree::
:maxdepth: 1
CMP0054: Only interpret if() arguments as variables or keywords when unquoted. </policy/CMP0054>
CMP0053: Simplify variable reference and escape sequence evaluation. </policy/CMP0053>
CMP0052: Reject source and build dirs in installed INTERFACE_INCLUDE_DIRECTORIES. </policy/CMP0052>
CMP0051: List TARGET_OBJECTS in SOURCES target property. </policy/CMP0051>
.. _`Policies Introduced by CMake 3.0`:
Policies Introduced by CMake 3.0, Removed by CMake 4.0
------------------------------------------------------
.. toctree::
:maxdepth: 1
CMP0050: Disallow add_custom_command SOURCE signatures. </policy/CMP0050>
CMP0049: Do not expand variables in target source entries. </policy/CMP0049>
CMP0048: project() command manages VERSION variables. </policy/CMP0048>
CMP0047: Use QCC compiler id for the qcc drivers on QNX. </policy/CMP0047>
CMP0046: Error on non-existent dependency in add_dependencies. </policy/CMP0046>
CMP0045: Error on non-existent target in get_target_property. </policy/CMP0045>
CMP0044: Case sensitive Lang_COMPILER_ID generator expressions. </policy/CMP0044>
CMP0043: Ignore COMPILE_DEFINITIONS_Config properties. </policy/CMP0043>
CMP0042: MACOSX_RPATH is enabled by default. </policy/CMP0042>
CMP0041: Error on relative include with generator expression. </policy/CMP0041>
CMP0040: The target in the TARGET signature of add_custom_command() must exist. </policy/CMP0040>
CMP0039: Utility targets may not have link dependencies. </policy/CMP0039>
CMP0038: Targets may not link directly to themselves. </policy/CMP0038>
CMP0037: Target names should not be reserved and should match a validity pattern. </policy/CMP0037>
CMP0036: The build_name command should not be called. </policy/CMP0036>
CMP0035: The variable_requires command should not be called. </policy/CMP0035>
CMP0034: The utility_source command should not be called. </policy/CMP0034>
CMP0033: The export_library_dependencies command should not be called. </policy/CMP0033>
CMP0032: The output_required_files command should not be called. </policy/CMP0032>
CMP0031: The load_command command should not be called. </policy/CMP0031>
CMP0030: The use_mangled_mesa command should not be called. </policy/CMP0030>
CMP0029: The subdir_depends command should not be called. </policy/CMP0029>
CMP0028: Double colon in target name means ALIAS or IMPORTED target. </policy/CMP0028>
CMP0027: Conditionally linked imported targets with missing include directories. </policy/CMP0027>
CMP0026: Disallow use of the LOCATION target property. </policy/CMP0026>
CMP0025: Compiler id for Apple Clang is now AppleClang. </policy/CMP0025>
CMP0024: Disallow include export result. </policy/CMP0024>
.. _`Policies Introduced by CMake 2.8`:
Policies Introduced by CMake 2.8, Removed by CMake 4.0
------------------------------------------------------
.. toctree::
:maxdepth: 1
CMP0023: Plain and keyword target_link_libraries signatures cannot be mixed. </policy/CMP0023>
CMP0022: INTERFACE_LINK_LIBRARIES defines the link interface. </policy/CMP0022>
CMP0021: Fatal error on relative paths in INCLUDE_DIRECTORIES target property. </policy/CMP0021>
CMP0020: Automatically link Qt executables to qtmain target on Windows. </policy/CMP0020>
CMP0019: Do not re-expand variables in include and link information. </policy/CMP0019>
CMP0018: Ignore CMAKE_SHARED_LIBRARY_Lang_FLAGS variable. </policy/CMP0018>
CMP0017: Prefer files from the CMake module directory when including from there. </policy/CMP0017>
CMP0016: target_link_libraries() reports error if its only argument is not a target. </policy/CMP0016>
CMP0015: link_directories() treats paths relative to the source dir. </policy/CMP0015>
CMP0014: Input directories must have CMakeLists.txt. </policy/CMP0014>
CMP0013: Duplicate binary directories are not allowed. </policy/CMP0013>
CMP0012: if() recognizes numbers and boolean constants. </policy/CMP0012>
.. _`Policies Introduced by CMake 2.6`:
Policies Introduced by CMake 2.6, Removed by CMake 4.0
------------------------------------------------------
.. toctree::
:maxdepth: 1
CMP0011: Included scripts do automatic cmake_policy PUSH and POP. </policy/CMP0011>
CMP0010: Bad variable reference syntax is an error. </policy/CMP0010>
CMP0009: FILE GLOB_RECURSE calls should not follow symlinks by default. </policy/CMP0009>
CMP0008: Libraries linked by full-path must have a valid library file name. </policy/CMP0008>
CMP0007: list command no longer ignores empty elements. </policy/CMP0007>
CMP0006: Installing MACOSX_BUNDLE targets requires a BUNDLE DESTINATION. </policy/CMP0006>
CMP0005: Preprocessor definition values are now escaped automatically. </policy/CMP0005>
CMP0004: Libraries linked may not have leading or trailing whitespace. </policy/CMP0004>
CMP0003: Libraries linked via full path no longer produce linker search paths. </policy/CMP0003>
CMP0002: Logical target names must be globally unique. </policy/CMP0002>
CMP0001: CMAKE_BACKWARDS_COMPATIBILITY should no longer be used. </policy/CMP0001>
CMP0000: A minimum required CMake version must be specified. </policy/CMP0000>