CMake/Help/command/FIND_XXX.txt
Craig Scott 049dbdd38c Help: Document that <PackageName>_ROOT applies to config packages too
The original intent of <PackageName>_ROOT may have been for it
to apply only to Find modules, but the implementation of the
find_package() command treats modules and config packages the
same. Both result in a <PackageName>_ROOT variable being
pushed onto the stack of package roots. A config package can
also call other find_...() commands, the behavior doesn't apply
just to find modules.
2019-10-27 16:10:09 +11:00

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A short-hand signature is:
.. parsed-literal::
|FIND_XXX| (<VAR> name1 [path1 path2 ...])
The general signature is:
.. parsed-literal::
|FIND_XXX| (
<VAR>
name | |NAMES|
[HINTS path1 [path2 ... ENV var]]
[PATHS path1 [path2 ... ENV var]]
[PATH_SUFFIXES suffix1 [suffix2 ...]]
[DOC "cache documentation string"]
[NO_DEFAULT_PATH]
[NO_PACKAGE_ROOT_PATH]
[NO_CMAKE_PATH]
[NO_CMAKE_ENVIRONMENT_PATH]
[NO_SYSTEM_ENVIRONMENT_PATH]
[NO_CMAKE_SYSTEM_PATH]
[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 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``, and the search will be attempted again the
next time |FIND_XXX| is invoked with the same variable.
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.
``PATH_SUFFIXES``
Specify additional subdirectories to check below each directory
location otherwise considered.
``DOC``
Specify the documentation string for the ``<VAR>`` cache entry.
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:
.. |FIND_PACKAGE_ROOT_PREFIX_PATH_XXX_SUBDIR| replace::
|prefix_XXX_SUBDIR| for each ``<prefix>`` in the
:variable:`<PackageName>_ROOT` CMake variable and the
:envvar:`<PackageName>_ROOT` environment variable if
called from within a find module loaded by
:command:`find_package(<PackageName>)`
.. |CMAKE_PREFIX_PATH_XXX_SUBDIR| replace::
|prefix_XXX_SUBDIR| for each ``<prefix>`` in :variable:`CMAKE_PREFIX_PATH`
.. |SYSTEM_ENVIRONMENT_PREFIX_PATH_XXX_SUBDIR| replace::
|prefix_XXX_SUBDIR| for each ``<prefix>/[s]bin`` in ``PATH``, and
|entry_XXX_SUBDIR| for other entries in ``PATH``
.. |CMAKE_SYSTEM_PREFIX_PATH_XXX_SUBDIR| replace::
|prefix_XXX_SUBDIR| for each ``<prefix>`` in
:variable:`CMAKE_SYSTEM_PREFIX_PATH`
1. If called from within a find module or any other script loaded by a call to
:command:`find_package(<PackageName>)`, search prefixes unique to the
current package being found. Specifically, look in the
:variable:`<PackageName>_ROOT` CMake variable and the
:envvar:`<PackageName>_ROOT` environment variable.
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 :variable:`CMAKE_FIND_USE_PACKAGE_ROOT_PATH` to ``FALSE``.
See policy :policy:`CMP0074`.
* |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 :ref:`semicolon-separated lists <CMake Language Lists>`.
This can be skipped if ``NO_CMAKE_PATH`` is passed or by setting the
:variable:`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 :variable:`CMAKE_FIND_USE_CMAKE_ENVIRONMENT_PATH` to ``FALSE``.
* |CMAKE_PREFIX_PATH_XXX|
* |CMAKE_XXX_PATH|
* |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 :variable:`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. This can be skipped if ``NO_CMAKE_SYSTEM_PATH``
is passed or by setting the :variable:`CMAKE_FIND_USE_CMAKE_SYSTEM_PATH`
to ``FALSE``.
* |CMAKE_SYSTEM_PREFIX_PATH_XXX|
* |CMAKE_SYSTEM_XXX_PATH|
* |CMAKE_SYSTEM_XXX_MAC_PATH|
7. Search the paths specified by the PATHS option
or in the short-hand version of the command.
These are typically hard-coded guesses.
.. |FIND_ARGS_XXX| replace:: <VAR> NAMES name
On macOS the :variable:`CMAKE_FIND_FRAMEWORK` and
:variable:`CMAKE_FIND_APPBUNDLE` variables determine the order of
preference between Apple-style and unix-style package components.
.. include:: FIND_XXX_ROOT.txt
.. include:: FIND_XXX_ORDER.txt