CMP0192 — CMake 4.2.6 Documentation

# CMP0192

Added in version 4.1.

`GNUInstallDirs` uses absolute `SYSCONFDIR`, `LOCALSTATEDIR`, and `RUNSTATEDIR` in special prefixes.

The `GNUInstallDirs` module documents special cases for `SYSCONFDIR`, `LOCALSTATEDIR`, and `RUNSTATEDIR`. When `CMAKE_INSTALL_PREFIX` is a special prefix, e.g., `/usr`, the absolute paths for these directories may be outside the prefix, e.g., `/etc`, `/var`, and `/var/run`.

In CMake 4.0 and below, the default values for the `CMAKE_INSTALL_<dir>` variables, for `<dir>` equal to `SYSCONFDIR`, `LOCALSTATEDIR`, and `RUNSTATEDIR`, always used relative paths (`etc`, `var`, `var/run`), and the special cases were implemented only when computing absolute paths for the `CMAKE_INSTALL_FULL_<dir>` variables. CMake 4.1 and above prefer to default `CMAKE_INSTALL_<dir>` variables to absolute paths, for `<dir>` equal to `SYSCONFDIR`, `LOCALSTATEDIR`, and `RUNSTATEDIR`, when `CMAKE_INSTALL_PREFIX` is a special prefix. This policy provides compatibility for projects that have not been updated to expect this behavior.

The `OLD` behavior for this policy is to default `CMAKE_INSTALL_<dir>` variables to relative paths. The `NEW` behavior for this policy is to default `CMAKE_INSTALL_<dir>` variables to absolute paths, for `<dir>` equal to `SYSCONFDIR`, `LOCALSTATEDIR`, and `RUNSTATEDIR`, when `CMAKE_INSTALL_PREFIX` is a special prefix.

This policy takes effect at the first call of `include(GNUInstallDirs)`. Subsequent calls of `include(GNUInstallDirs)` reuse cached `CMAKE_INSTALL_<dir>` values from the first call.

This policy was introduced in CMake version 4.1. 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.