Policies

CMake's policy system allows for backwards compatibility with older CMake implementations, allowing for older projects to "just work" out of the box. However, when including these older projects as children, policy scoping may end up being incorrect, and even if a given policy was set manually by a parent project, the policy might be ignored.

However CMake provides an escape hatch to set default values for policies when entering a "fresh" policy state. This escape hatch relies on a user setting the CMAKE_POLICY_DEFAULT_CMP<Policy Number Here> variable.

Some policy values are absolutely necessary to be defaulted simply for user's sanity and IXM does this to ensure that anyone calling add_subdirectory on a subproject is guaranteed some specific behavior. Every policy documented below is set to the NEW value.

CMP0180

De-duplication of static libraries on link lines keeps first occurrence

CMP0180

project() will always set the <PROJECT_NAME>_* values as normal variables.

CMP0177

TODO

CMP0176

TODO

CMP0175

TODO

CMP0174

TODO

CMP0172

TODO

CMP0171

codegen is a reserved target name.

CMP0160

More read only properties not error when trying to set them.

CMP0144

find_package supports upper-case PACKAGENAME_ROOT variables.

CMP0130

while() diagnoses condition evaluation errors.

CMP0125

find_<...>() functions have consistent cache variable behavior.

CMP0124

foreach() loop variables are scoped.

CMP0121

list() detects invalid indices

CMP0116

Ninja transforms DEPFILES in add_custom_command.

CMP0092

MSVC warning flags are removed by default.

CMP0091

MSVC uses the CMAKE_MSVC_RUNTIME_LIBRARY variable.

CMP0090

export(PACKAGE) does not populate package registry.

CMP0077

option() honors normal variables.