CMP0215

Added in version 4.4.

Ninja Generators emit Swift modules separately from compilation.

In CMake 4.3 and below, Swift targets built by Ninja Generators emit .swiftmodule from the Swift compile edge together with object files. Because Ninja treats a build edge as atomic, downstream Swift targets must wait for compilation outputs to finish before they can use the module interface.

CMake 4.4 and above prefer to emit .swiftmodule from a dedicated -emit-module build edge so that downstream Swift targets can begin compiling as soon as the module interface is available. This policy provides compatibility with projects that have not been updated.

The OLD behavior for this policy is to not emit modules separately. The NEW behavior for this policy is to emit .swiftmodule from a dedicated build edge for importable Swift targets by default.

The Swift_SEPARATE_MODULE_EMISSION target property and corresponding CMAKE_Swift_SEPARATE_MODULE_EMISSION variable may be set to enable or disable the behavior on a per-target basis.

The NEW behavior requires that policies CMP0157 and CMP0195 are also set to NEW. CMP0157 selects the split Swift build model that provides the dedicated .swiftmodule edge, and must be set prior to the first project() or enable_language() command that enables the Swift language. CMP0195 places the module in the Swift module directory structure that the dedicated edge writes. If either policy is not NEW while CMP0215 is NEW, CMake issues a fatal error when the Swift language is enabled.

This policy was introduced in CMake version 4.4. It may be set by cmake_policy() or cmake_minimum_required(). If it is not set, CMake does not warn, and uses OLD behavior.

Note

The OLD behavior of a policy is deprecated by definition and may be removed in a future version of CMake.