CMake/Help/policy/CMP0043.rst

CMP0043
-------

Ignore COMPILE_DEFINITIONS_<Config> properties

CMake 2.8.12 and lower allowed setting the
:prop_tgt:`COMPILE_DEFINITIONS_<CONFIG>` target property and
:prop_dir:`COMPILE_DEFINITIONS_<CONFIG>` directory property to apply
configuration-specific compile definitions.

Since CMake 2.8.10, the :prop_tgt:`COMPILE_DEFINITIONS` property has supported
:manual:`generator expressions <cmake-generator-expressions(7)>` for setting
configuration-dependent content.  The continued existence of the suffixed
variables is redundant, and causes a maintenance burden.  Population of the
:prop_tgt:`COMPILE_DEFINITIONS_DEBUG <COMPILE_DEFINITIONS_<CONFIG>>` property
may be replaced with a population of :prop_tgt:`COMPILE_DEFINITIONS` directly
or via :command:`target_compile_definitions`:

.. code-block:: cmake

  # Old Interface:
  set_property(TARGET tgt APPEND PROPERTY
    COMPILE_DEFINITIONS_DEBUG DEBUG_MODE
  )

  # New Interfaces:
  set_property(TARGET tgt APPEND PROPERTY
    COMPILE_DEFINITIONS $<$<CONFIG:Debug>:DEBUG_MODE>
  )
  target_compile_definitions(tgt PRIVATE $<$<CONFIG:Debug>:DEBUG_MODE>)

The OLD behavior for this policy is to consume the content of the suffixed
:prop_tgt:`COMPILE_DEFINITIONS_<CONFIG>` target property when generating the
compilation command. The NEW behavior for this policy is to ignore the content
of the :prop_tgt:`COMPILE_DEFINITIONS_<CONFIG>` target property .

This policy was introduced in CMake version 3.0.  CMake version
|release| warns when the policy is not set and uses OLD behavior.  Use
the cmake_policy command to set it to OLD or NEW explicitly.