CMake/Help/command/add_definitions.rst

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

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

::

  add_definitions(-DFOO -DBAR ...)

Adds definitions to the compiler command line for sources in the current
directory and below.  This command can be used to add any flags, but
it is intended to add preprocessor definitions.  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.

Arguments to ``add_definitions`` may use "generator expressions" with
the syntax "$<...>".  See the :manual:`cmake-generator-expressions(7)`
manual for available expressions.  See the :manual:`cmake-buildsystem(7)`
manual for more on defining buildsystem properties.