# CMAKE_REQUIRE_FIND_PACKAGE_<PackageName>

New in version 3.22.

Variable for making `find_package()` call `REQUIRED`.

Every non-`REQUIRED` `find_package()` call in a project can be turned into `REQUIRED` by setting the variable `CMAKE_REQUIRE_FIND_PACKAGE_<PackageName>` to `TRUE`. This can be used to assert assumptions about build environment and to ensure the build will fail early if they do not hold.

Note that setting this variable to true breaks some commonly used patterns. Multiple calls to `find_package()` are sometimes used to obtain a different search order to the default. For example, projects can force checking a known path for a particular package first before searching any of the other default search paths:

    find_package(something PATHS /some/local/path NO_DEFAULT_PATH)
    find_package(something)

In the above, the first call looks for the `something` package in a specific directory. If `CMAKE_REQUIRE_FIND_PACKAGE_something` is set to true, then this first call must succeed, otherwise a fatal error occurs. The second call never gets a chance to provide a fall-back to using the default search locations.

A similar pattern is used even by some of CMake's own Find modules to search for a config package first:

    find_package(something CONFIG QUIET)
    if(NOT something_FOUND)
      # Fall back to searching using typical Find module logic...
    endif()

Again, if `CMAKE_REQUIRE_FIND_PACKAGE_something` is true, the first call must succeed. It effectively means a config package must be found for the dependency, and the Find module logic is never used.

See also the `CMAKE_DISABLE_FIND_PACKAGE_<PackageName>` variable.