CMake/Help/command/add_definitions.rst

add_definitions
---------------

Add -D define flags to the compilation of source files.

.. code-block:: cmake

  add_definitions(-DFOO -DBAR ...)

Adds definitions to the compiler command line for targets in the current
directory and below (whether added before or after this command is invoked).
This command can be used to add any flags, but it is intended to add
preprocessor definitions.

.. note::

  This command has been superseded by alternatives:

  * Use :command:`add_compile_definitions` to add preprocessor definitions.
  * Use :command:`include_directories` to add include directories.
  * Use :command:`add_compile_options` to add other options.

Flags beginning in -D or /D that look like preprocessor definitions are
automatically added to the :prop_dir:`COMPILE_DEFINITIONS` directory
property for the current directory.  Definitions with non-trivial values
may be left in the set of flags instead of being converted for reasons of
backwards compatibility.  See documentation of the
:prop_dir:`directory <COMPILE_DEFINITIONS>`,
:prop_tgt:`target <COMPILE_DEFINITIONS>`,
:prop_sf:`source file <COMPILE_DEFINITIONS>` ``COMPILE_DEFINITIONS``
properties for details on adding preprocessor definitions to specific
scopes and configurations.

See the :manual:`cmake-buildsystem(7)` manual for more on defining
buildsystem properties.