CMP0116 ------- .. versionadded:: 3.20 Ninja generators transform ``DEPFILE`` s from :command:`add_custom_command`. In CMake 3.19 and below, files given to the ``DEPFILE`` argument of :command:`add_custom_command` were passed directly to Ninja's ``depfile`` variable without any path resolution. This meant that if :command:`add_custom_command` was called from a subdirectory (created by :command:`add_subdirectory`), the ``DEPFILE`` argument would have to be either an absolute path or a path relative to :variable:`CMAKE_BINARY_DIR`, rather than :variable:`CMAKE_CURRENT_BINARY_DIR`. In addition, no transformation was done on the file listed in ``DEPFILE``, which meant that the paths within the ``DEPFILE`` had the same restrictions. Starting with CMake 3.20, the ``DEPFILE`` argument is relative to :variable:`CMAKE_CURRENT_BINARY_DIR` (unless it is absolute), and the paths in the ``DEPFILE`` are also relative to :variable:`CMAKE_CURRENT_BINARY_DIR`. CMake automatically transforms the paths in the ``DEPFILE`` (unless they are absolute) after the custom command is run. The file listed in ``DEPFILE`` is not modified in any way. Instead, CMake writes the transformation to its own internal file, and passes this internal file to Ninja's ``depfile`` variable. This transformation happens regardless of whether or not ``DEPFILE`` is relative, and regardless of whether or not :command:`add_custom_command` is called from a subdirectory. The ``OLD`` behavior for this policy is to pass the ``DEPFILE`` to Ninja unaltered. The ``NEW`` behavior for this policy is to transform the ``DEPFILE`` after running the custom command. The status of ``CMP0116`` is recorded at the time of the custom command's creation, and you can have custom commands in the same directory with different values for ``CMP0116`` by setting the policy before each custom command. This policy was introduced in CMake version 3.20. Unlike most policies, CMake version |release| does *not* warn by default when this policy is not set (unless ``DEPFILE`` is used in a subdirectory) and simply uses ``OLD`` behavior. See documentation of the :variable:`CMAKE_POLICY_WARNING_CMP0116 >` variable to control the warning.