A short-hand signature is:

|FIND_XXX| (<VAR> name1 [path1 path2 ...])

The general signature is:

|FIND_XXX| (
          <VAR>
          name | |NAMES|
          [HINTS [path | ENV var]...]
          [PATHS [path | ENV var]...]
          [REGISTRY_VIEW (64|32|64_32|32_64|HOST|TARGET|BOTH)]
          [PATH_SUFFIXES suffix1 [suffix2 ...]]
          [VALIDATOR function]
          [DOC "cache documentation string"]
          [NO_CACHE]
          [REQUIRED|OPTIONAL]
          [NO_DEFAULT_PATH]
          [NO_PACKAGE_ROOT_PATH]
          [NO_CMAKE_PATH]
          [NO_CMAKE_ENVIRONMENT_PATH]
          [NO_SYSTEM_ENVIRONMENT_PATH]
          [NO_CMAKE_SYSTEM_PATH]
          [NO_CMAKE_INSTALL_PREFIX]
          [CMAKE_FIND_ROOT_PATH_BOTH |
           ONLY_CMAKE_FIND_ROOT_PATH |
           NO_CMAKE_FIND_ROOT_PATH]
         )

This command is used to find a |SEARCH_XXX_DESC|. A cache entry, or a normal variable if NO_CACHE is specified, named by <VAR> is created to store the result of this command. If the |SEARCH_XXX| is found the result is stored in the variable and the search will not be repeated unless the variable is cleared. If nothing is found, the result will be <VAR>-NOTFOUND.

Options include:

NAMES

Specify one or more possible names for the |SEARCH_XXX|.

When using this to specify names with and without a version suffix, we recommend specifying the unversioned name first so that locally-built packages can be found before those provided by distributions.

HINTS, PATHS

Specify directories to search in addition to the default locations. The ENV var sub-option reads paths from a system environment variable.

Changed in version 3.24: On Windows platform, it is possible to include registry queries as part of the directories, using a dedicated syntax. Such specifications will be ignored on all other platforms.

REGISTRY_VIEW

Added in version 3.24.

PATH_SUFFIXES

Specify additional subdirectories to check below each directory location otherwise considered.

VALIDATOR

Added in version 3.25.

Specify a function() to be called for each candidate item found (a macro() cannot be provided, that will result in an error). Two arguments will be passed to the validator function: the name of a result variable, and the absolute path to the candidate item. The item will be accepted and the search will end unless the function sets the value in the result variable to false in the calling scope. The result variable will hold a true value when the validator function is entered.

function(my_check validator_result_var item)
  if(NOT item MATCHES ...)
    set(${validator_result_var} FALSE PARENT_SCOPE)
  endif()
endfunction()

|FIND_XXX| (result NAMES ... VALIDATOR my_check)

Note that if a cached result is used, the search is skipped and any VALIDATOR is ignored. The cached result is not required to pass the validation function.

DOC

Specify the documentation string for the <VAR> cache entry.

NO_CACHE

Added in version 3.21.

The result of the search will be stored in a normal variable rather than a cache entry.

Note

If the variable is already set before the call (as a normal or cache variable) then the search will not occur.

Warning

This option should be used with caution because it can greatly increase the cost of repeated configure steps.

REQUIRED

Added in version 3.18.

Stop processing with an error message if nothing is found, otherwise the search will be attempted again the next time |FIND_XXX| is invoked with the same variable.

Added in version 4.1: Every |FIND_XXX| command will be treated as REQUIRED when the CMAKE_FIND_REQUIRED variable is enabled.

OPTIONAL

Added in version 4.1.

Ignore the value of CMAKE_FIND_REQUIRED and continue without an error message if nothing is found. Incompatible with REQUIRED.

If NO_DEFAULT_PATH is specified, then no additional paths are added to the search. If NO_DEFAULT_PATH is not specified, the search process is as follows:

1. If called from within a find module or any other script loaded by a call to find_package(<PackageName>), search prefixes unique to the current package being found. See policy CMP0074.

   Added in version 3.12.

   Specifically, search paths specified by the following variables, in order:

   1. <PackageName>_ROOT CMake variable, where <PackageName> is the case-preserved package name.

   2. <PACKAGENAME>_ROOT CMake variable, where <PACKAGENAME> is the upper-cased package name. See policy CMP0144.

      Added in version 3.27.

   3. <PackageName>_ROOT environment variable, where <PackageName> is the case-preserved package name.

   4. <PACKAGENAME>_ROOT environment variable, where <PACKAGENAME> is the upper-cased package name. See policy CMP0144.

      Added in version 3.27.

   The package root variables are maintained as a stack, so if called from nested find modules or config packages, root paths from the parent's find module or config package will be searched after paths from the current module or package. In other words, the search order would be <CurrentPackage>_ROOT, ENV{<CurrentPackage>_ROOT}, <ParentPackage>_ROOT, ENV{<ParentPackage>_ROOT}, etc. This can be skipped if NO_PACKAGE_ROOT_PATH is passed or by setting the CMAKE_FIND_USE_PACKAGE_ROOT_PATH to FALSE.

   • |FIND_PACKAGE_ROOT_PREFIX_PATH_XXX|

2. Search paths specified in cmake-specific cache variables. These are intended to be used on the command line with a -DVAR=value. The values are interpreted as semicolon-separated lists. This can be skipped if NO_CMAKE_PATH is passed or by setting the CMAKE_FIND_USE_CMAKE_PATH to FALSE.

   • |CMAKE_PREFIX_PATH_XXX|

   • |CMAKE_XXX_PATH|

   • |CMAKE_XXX_MAC_PATH|

3. Search paths specified in cmake-specific environment variables. These are intended to be set in the user's shell configuration, and therefore use the host's native path separator (; on Windows and : on UNIX). This can be skipped if NO_CMAKE_ENVIRONMENT_PATH is passed or by setting the CMAKE_FIND_USE_CMAKE_ENVIRONMENT_PATH to FALSE.

   • |ENV_CMAKE_PREFIX_PATH_XXX|

   • |ENV_CMAKE_XXX_PATH|

   • |ENV_CMAKE_XXX_MAC_PATH|

4. Search the paths specified by the HINTS option. These should be paths computed by system introspection, such as a hint provided by the location of another item already found. Hard-coded guesses should be specified with the PATHS option.

5. Search the standard system environment variables. This can be skipped if NO_SYSTEM_ENVIRONMENT_PATH is passed or by setting the CMAKE_FIND_USE_SYSTEM_ENVIRONMENT_PATH to FALSE.

   • |SYSTEM_ENVIRONMENT_PATH_XXX|

   |SYSTEM_ENVIRONMENT_PATH_WINDOWS_XXX|

6. Search cmake variables defined in the Platform files for the current system. The searching of CMAKE_INSTALL_PREFIX and CMAKE_STAGING_PREFIX can be skipped if NO_CMAKE_INSTALL_PREFIX is passed or by setting the CMAKE_FIND_USE_INSTALL_PREFIX to FALSE. All these locations can be skipped if NO_CMAKE_SYSTEM_PATH is passed or by setting the CMAKE_FIND_USE_CMAKE_SYSTEM_PATH to FALSE.

   • |CMAKE_SYSTEM_PREFIX_PATH_XXX|

   • |CMAKE_SYSTEM_XXX_PATH|

   • |CMAKE_SYSTEM_XXX_MAC_PATH|

   The platform paths that these variables contain are locations that typically include installed software. An example being /usr/local for UNIX based platforms.

7. Search the paths specified by the PATHS option or in the short-hand version of the command. These are typically hard-coded guesses.

The CMAKE_IGNORE_PATH, CMAKE_IGNORE_PREFIX_PATH, CMAKE_SYSTEM_IGNORE_PATH and CMAKE_SYSTEM_IGNORE_PREFIX_PATH variables can also cause some of the above locations to be ignored.

Added in version 3.16: Added CMAKE_FIND_USE_<CATEGORY>_PATH variables to globally disable various search locations.

On macOS the CMAKE_FIND_FRAMEWORK and CMAKE_FIND_APPBUNDLE variables determine the order of preference between Apple-style and unix-style package components.