CMAKE_Swift_SEPARATE_MODULE_EMISSION

.. versionadded:: 4.4

Specify whether Swift targets emit .swiftmodule from a dedicated build edge. This variable is used to initialize the :prop_tgt:Swift_SEPARATE_MODULE_EMISSION property on targets as they are created.

When set to ON, importable Swift targets built by :ref:Ninja Generators produce the .swiftmodule from a separate -emit-module build edge, allowing downstream Swift targets to compile in parallel with upstream object compilation.

If this variable is not set, separate module emission is enabled by default in targets that do not set :prop_tgt:Swift_SEPARATE_MODULE_EMISSION. See policy :policy:CMP0215.

.. note::

Separate module emission takes effect only when policy :policy:CMP0157 is set to NEW prior to the first :command:project or :command:enable_language command that enables the Swift language.