1 # Distributed under the OSI-approved BSD 3-Clause License. See accompanying
2 # file Copyright.txt or https://cmake.org/licensing for details.
4 #[=======================================================================[.rst:
14 .. note:: The :guide:`Using Dependencies Guide` provides a high-level
15 introduction to this general topic. It provides a broader overview of
16 where the ``FetchContent`` module fits into the bigger picture,
17 including its relationship to the :command:`find_package` command.
18 The guide is recommended pre-reading before moving on to the details below.
23 This module enables populating content at configure time via any method
24 supported by the :module:`ExternalProject` module. Whereas
25 :command:`ExternalProject_Add` downloads at build time, the
26 ``FetchContent`` module makes content available immediately, allowing the
27 configure step to use the content in commands like :command:`add_subdirectory`,
28 :command:`include` or :command:`file` operations.
30 Content population details should be defined separately from the command that
31 performs the actual population. This separation ensures that all the
32 dependency details are defined before anything might try to use them to
33 populate content. This is particularly important in more complex project
34 hierarchies where dependencies may be shared between multiple projects.
36 The following shows a typical example of declaring content details for some
37 dependencies and then ensuring they are populated with a separate call:
43 GIT_REPOSITORY https://github.com/google/googletest.git
44 GIT_TAG 703bd9caab50b139428cea1aaff9974ebee5742e # release-1.10.0
48 URL https://intranet.mycompany.com/assets/iconset_1.12.tar.gz
49 URL_HASH MD5=5588a7b18261c20068beabfb4f530b87
52 FetchContent_MakeAvailable(googletest myCompanyIcons)
54 The :command:`FetchContent_MakeAvailable` command ensures the named
55 dependencies have been populated, either by an earlier call or by populating
56 them itself. When performing the population, it will also add them to the
57 main build, if possible, so that the main build can use the populated
58 projects' targets, etc. See the command's documentation for how these steps
61 When using a hierarchical project arrangement, projects at higher levels in
62 the hierarchy are able to override the declared details of content specified
63 anywhere lower in the project hierarchy. The first details to be declared
64 for a given dependency take precedence, regardless of where in the project
65 hierarchy that occurs. Similarly, the first call that tries to populate a
66 dependency "wins", with subsequent populations reusing the result of the
67 first instead of repeating the population again.
68 See the :ref:`Examples <fetch-content-examples>` which demonstrate
71 In some cases, the main project may need to have more precise control over
72 the population, or it may be required to explicitly define the population
73 steps in a way that cannot be captured by the declared details alone.
74 For such situations, the lower level :command:`FetchContent_GetProperties` and
75 :command:`FetchContent_Populate` commands can be used. These lack the richer
76 features provided by :command:`FetchContent_MakeAvailable` though, so their
77 direct use should be considered a last resort. The typical pattern of such
78 custom steps looks like this:
82 # NOTE: Where possible, prefer to use FetchContent_MakeAvailable()
83 # instead of custom logic like this
85 # Check if population has already been performed
86 FetchContent_GetProperties(depname)
87 if(NOT depname_POPULATED)
88 # Fetch the content using previously declared details
89 FetchContent_Populate(depname)
91 # Set custom variables, policies, etc.
94 # Bring the populated content into the build
95 add_subdirectory(${depname_SOURCE_DIR} ${depname_BINARY_DIR})
98 The ``FetchContent`` module also supports defining and populating
99 content in a single call, with no check for whether the content has been
100 populated elsewhere already. This should not be done in projects, but may
101 be appropriate for populating content in CMake's script mode.
102 See :command:`FetchContent_Populate` for details.
107 .. command:: FetchContent_Declare
109 .. code-block:: cmake
111 FetchContent_Declare(
114 [OVERRIDE_FIND_PACKAGE |
115 FIND_PACKAGE_ARGS args...]
118 The ``FetchContent_Declare()`` function records the options that describe
119 how to populate the specified content. If such details have already
120 been recorded earlier in this project (regardless of where in the project
121 hierarchy), this and all later calls for the same content ``<name>`` are
122 ignored. This "first to record, wins" approach is what allows hierarchical
123 projects to have parent projects override content details of child projects.
125 The content ``<name>`` can be any string without spaces, but good practice
126 would be to use only letters, numbers and underscores. The name will be
127 treated case-insensitively and it should be obvious for the content it
128 represents, often being the name of the child project or the value given
129 to its top level :command:`project` command (if it is a CMake project).
130 For well-known public projects, the name should generally be the official
131 name of the project. Choosing an unusual name makes it unlikely that other
132 projects needing that same content will use the same name, leading to
133 the content being populated multiple times.
135 The ``<contentOptions>`` can be any of the download, update or patch options
136 that the :command:`ExternalProject_Add` command understands. The configure,
137 build, install and test steps are explicitly disabled and therefore options
138 related to them will be ignored. The ``SOURCE_SUBDIR`` option is an
139 exception, see :command:`FetchContent_MakeAvailable` for details on how that
142 In most cases, ``<contentOptions>`` will just be a couple of options defining
143 the download method and method-specific details like a commit tag or archive
146 .. code-block:: cmake
148 FetchContent_Declare(
150 GIT_REPOSITORY https://github.com/google/googletest.git
151 GIT_TAG 703bd9caab50b139428cea1aaff9974ebee5742e # release-1.10.0
154 FetchContent_Declare(
156 URL https://intranet.mycompany.com/assets/iconset_1.12.tar.gz
157 URL_HASH MD5=5588a7b18261c20068beabfb4f530b87
160 FetchContent_Declare(
161 myCompanyCertificates
162 SVN_REPOSITORY svn+ssh://svn.mycompany.com/srv/svn/trunk/certs
166 Where contents are being fetched from a remote location and you do not
167 control that server, it is advisable to use a hash for ``GIT_TAG`` rather
168 than a branch or tag name. A commit hash is more secure and helps to
169 confirm that the downloaded contents are what you expected.
171 .. versionchanged:: 3.14
172 Commands for the download, update or patch steps can access the terminal.
173 This may be needed for things like password prompts or real-time display
176 .. versionadded:: 3.22
177 The :variable:`CMAKE_TLS_VERIFY`, :variable:`CMAKE_TLS_CAINFO`,
178 :variable:`CMAKE_NETRC` and :variable:`CMAKE_NETRC_FILE` variables now
179 provide the defaults for their corresponding content options, just like
180 they do for :command:`ExternalProject_Add`. Previously, these variables
181 were ignored by the ``FetchContent`` module.
183 .. versionadded:: 3.24
185 ``FIND_PACKAGE_ARGS``
186 This option is for scenarios where the
187 :command:`FetchContent_MakeAvailable` command may first try a call to
188 :command:`find_package` to satisfy the dependency for ``<name>``.
189 By default, such a call would be simply ``find_package(<name>)``, but
190 ``FIND_PACKAGE_ARGS`` can be used to provide additional arguments to be
191 appended after the ``<name>``. ``FIND_PACKAGE_ARGS`` can also be given
192 with nothing after it, which indicates that :command:`find_package` can
193 still be called if :variable:`FETCHCONTENT_TRY_FIND_PACKAGE_MODE` is
194 set to ``OPT_IN`` or is not set.
196 Everything after the ``FIND_PACKAGE_ARGS`` keyword is appended to the
197 :command:`find_package` call, so all other ``<contentOptions>`` must
198 come before the ``FIND_PACKAGE_ARGS`` keyword. If the
199 :variable:`CMAKE_FIND_PACKAGE_TARGETS_GLOBAL` variable is set to true
200 at the time ``FetchContent_Declare()`` is called, a ``GLOBAL`` keyword
201 will be appended to the :command:`find_package` arguments if it was
202 not already specified. It will also be appended if
203 ``FIND_PACKAGE_ARGS`` was not given, but
204 :variable:`FETCHCONTENT_TRY_FIND_PACKAGE_MODE` was set to ``ALWAYS``.
206 ``OVERRIDE_FIND_PACKAGE`` cannot be used when ``FIND_PACKAGE_ARGS`` is
209 :ref:`dependency_providers` discusses another way that
210 :command:`FetchContent_MakeAvailable` calls can be redirected.
211 ``FIND_PACKAGE_ARGS`` is intended for project control, whereas
212 dependency providers allow users to override project behavior.
214 ``OVERRIDE_FIND_PACKAGE``
215 When a ``FetchContent_Declare(<name> ...)`` call includes this option,
216 subsequent calls to ``find_package(<name> ...)`` will ensure that
217 ``FetchContent_MakeAvailable(<name>)`` has been called, then use the
218 config package files in the :variable:`CMAKE_FIND_PACKAGE_REDIRECTS_DIR`
219 directory (which are usually created by ``FetchContent_MakeAvailable()``).
220 This effectively makes :command:`FetchContent_MakeAvailable` override
221 :command:`find_package` for the named dependency, allowing the former to
222 satisfy the package requirements of the latter. ``FIND_PACKAGE_ARGS``
223 cannot be used when ``OVERRIDE_FIND_PACKAGE`` is given.
225 If a :ref:`dependency provider <dependency_providers>` has been set
226 and the project calls :command:`find_package` for the ``<name>``
227 dependency, ``OVERRIDE_FIND_PACKAGE`` will not prevent the provider
228 from seeing that call. Dependency providers always have the opportunity
229 to intercept any direct call to :command:`find_package`, except if that
230 call contains the ``BYPASS_PROVIDER`` option.
232 .. command:: FetchContent_MakeAvailable
234 .. versionadded:: 3.14
236 .. code-block:: cmake
238 FetchContent_MakeAvailable(<name1> [<name2>...])
240 This command ensures that each of the named dependencies are made available
241 to the project by the time it returns. There must have been a call to
242 :command:`FetchContent_Declare` for each dependency, and the first such call
243 will control how that dependency will be made available, as described below.
245 If ``<lowercaseName>_SOURCE_DIR`` is not set:
247 * .. versionadded:: 3.24
249 If a :ref:`dependency provider <dependency_providers>` is set, call the
250 provider's command with ``FETCHCONTENT_MAKEAVAILABLE_SERIAL`` as the
251 first argument, followed by the arguments of the first call to
252 :command:`FetchContent_Declare` for ``<name>``. If ``SOURCE_DIR`` or
253 ``BINARY_DIR`` were not part of the original declared arguments, they
254 will be added with their default values.
255 If :variable:`FETCHCONTENT_TRY_FIND_PACKAGE_MODE` was set to ``NEVER``
256 when the details were declared, any ``FIND_PACKAGE_ARGS`` will be
257 omitted. The ``OVERRIDE_FIND_PACKAGE`` keyword is also always omitted.
258 If the provider fulfilled the request, ``FetchContent_MakeAvailable()``
259 will consider that dependency handled, skip the remaining steps below
260 and move on to the next dependency in the list.
262 * .. versionadded:: 3.24
264 If permitted, :command:`find_package(<name> [<args>...]) <find_package>`
265 will be called, where ``<args>...`` may be provided by the
266 ``FIND_PACKAGE_ARGS`` option in :command:`FetchContent_Declare`.
267 The value of the :variable:`FETCHCONTENT_TRY_FIND_PACKAGE_MODE` variable
268 at the time :command:`FetchContent_Declare` was called determines whether
269 ``FetchContent_MakeAvailable()`` can call :command:`find_package`.
270 If the :variable:`CMAKE_FIND_PACKAGE_TARGETS_GLOBAL` variable is set to
271 true when ``FetchContent_MakeAvailable()`` is called, it still affects
272 any imported targets created when that in turn calls
273 :command:`find_package`, even if that variable was false when the
274 corresponding details were declared.
276 If the dependency was not satisfied by a provider or a
277 :command:`find_package` call, ``FetchContent_MakeAvailable()`` then uses
278 the following logic to make the dependency available:
280 * If the dependency has already been populated earlier in this run, set
281 the ``<lowercaseName>_POPULATED``, ``<lowercaseName>_SOURCE_DIR`` and
282 ``<lowercaseName>_BINARY_DIR`` variables in the same way as a call to
283 :command:`FetchContent_GetProperties`, then skip the remaining steps
284 below and move on to the next dependency in the list.
286 * Call :command:`FetchContent_Populate` to populate the dependency using
287 the details recorded by an earlier call to :command:`FetchContent_Declare`.
288 Halt with a fatal error if no such details have been recorded.
289 :variable:`FETCHCONTENT_SOURCE_DIR_<uppercaseName>` can be used to override
290 the declared details and use content provided at the specified location
293 * .. versionadded:: 3.24
295 Ensure the :variable:`CMAKE_FIND_PACKAGE_REDIRECTS_DIR` directory
296 contains a ``<lowercaseName>-config.cmake`` and a
297 ``<lowercaseName>-config-version.cmake`` file (or equivalently
298 ``<name>Config.cmake`` and ``<name>ConfigVersion.cmake``).
299 The directory that the :variable:`CMAKE_FIND_PACKAGE_REDIRECTS_DIR`
300 variable points to is cleared at the start of every CMake run.
301 If no config file exists when :command:`FetchContent_Populate` returns,
302 a minimal one will be written which :command:`includes <include>` any
303 ``<lowercaseName>-extra.cmake`` or ``<name>Extra.cmake`` file with the
304 ``OPTIONAL`` flag (so the files can be missing and won't generate a
305 warning). Similarly, if no config version file exists, a very simple
306 one will be written which sets ``PACKAGE_VERSION_COMPATIBLE`` to true.
307 CMake cannot automatically determine an arbitrary dependency's version,
308 so it cannot set ``PACKAGE_VERSION`` or ``PACKAGE_VERSION_EXACT``.
309 When a dependency is pulled in via :command:`add_subdirectory` in the
310 next step, it may choose to overwrite the generated config version file
311 in :variable:`CMAKE_FIND_PACKAGE_REDIRECTS_DIR` with one that also sets
312 ``PACKAGE_VERSION``, and if appropriate, ``PACKAGE_VERSION_EXACT``.
313 The dependency may also write a ``<lowercaseName>-extra.cmake`` or
314 ``<name>Extra.cmake`` file to perform custom processing or define any
315 variables that their normal (installed) package config file would
316 otherwise usually define (many projects don't do any custom processing
317 or set any variables and therefore have no need to do this).
318 If required, the main project can write these files instead if the
319 dependency project doesn't do so. This allows the main project to
320 add missing details from older dependencies that haven't or can't be
321 updated to support this functionality.
322 See `Integrating With find_package()`_ for examples.
324 * If the top directory of the populated content contains a ``CMakeLists.txt``
325 file, call :command:`add_subdirectory` to add it to the main build.
326 It is not an error for there to be no ``CMakeLists.txt`` file, which
327 allows the command to be used for dependencies that make downloaded
328 content available at a known location, but which do not need or support
329 being added directly to the build.
331 .. versionadded:: 3.18
332 The ``SOURCE_SUBDIR`` option can be given in the declared details to
333 look somewhere below the top directory instead (i.e. the same way that
334 ``SOURCE_SUBDIR`` is used by the :command:`ExternalProject_Add`
335 command). The path provided with ``SOURCE_SUBDIR`` must be relative
336 and will be treated as relative to the top directory. It can also
337 point to a directory that does not contain a ``CMakeLists.txt`` file
338 or even to a directory that doesn't exist. This can be used to avoid
339 adding a project that contains a ``CMakeLists.txt`` file in its top
342 Projects should aim to declare the details of all dependencies they might
343 use before they call ``FetchContent_MakeAvailable()`` for any of them.
344 This ensures that if any of the dependencies are also sub-dependencies of
345 one or more of the others, the main project still controls the details
346 that will be used (because it will declare them first before the
347 dependencies get a chance to). In the following code samples, assume that
348 the ``uses_other`` dependency also uses ``FetchContent`` to add the ``other``
349 dependency internally:
351 .. code-block:: cmake
353 # WRONG: Should declare all details first
354 FetchContent_Declare(uses_other ...)
355 FetchContent_MakeAvailable(uses_other)
357 FetchContent_Declare(other ...) # Will be ignored, uses_other beat us to it
358 FetchContent_MakeAvailable(other) # Would use details declared by uses_other
360 .. code-block:: cmake
362 # CORRECT: All details declared first, so they will take priority
363 FetchContent_Declare(uses_other ...)
364 FetchContent_Declare(other ...)
365 FetchContent_MakeAvailable(uses_other other)
367 Note that :variable:`CMAKE_VERIFY_INTERFACE_HEADER_SETS` is explicitly set
368 to false upon entry to ``FetchContent_MakeAvailable()``, and is restored to
369 its original value before the command returns. Developers typically only
370 want to verify header sets from the main project, not those from any
371 dependencies. This local manipulation of the
372 :variable:`CMAKE_VERIFY_INTERFACE_HEADER_SETS` variable provides that
373 intuitive behavior. You can use variables like
374 :variable:`CMAKE_PROJECT_INCLUDE` or
375 :variable:`CMAKE_PROJECT_<PROJECT-NAME>_INCLUDE` to turn verification back
376 on for all or some dependencies. You can also set the
377 :prop_tgt:`VERIFY_INTERFACE_HEADER_SETS` property of individual targets.
379 .. command:: FetchContent_Populate
382 Where possible, prefer to use :command:`FetchContent_MakeAvailable`
383 instead of implementing population manually with this command.
385 .. code-block:: cmake
387 FetchContent_Populate(<name>)
389 In most cases, the only argument given to ``FetchContent_Populate()`` is the
390 ``<name>``. When used this way, the command assumes the content details have
391 been recorded by an earlier call to :command:`FetchContent_Declare`. The
392 details are stored in a global property, so they are unaffected by things
393 like variable or directory scope. Therefore, it doesn't matter where in the
394 project the details were previously declared, as long as they have been
395 declared before the call to ``FetchContent_Populate()``. Those saved details
396 are then used to construct a call to :command:`ExternalProject_Add` in a
397 private sub-build to perform the content population immediately. The
398 implementation of ``ExternalProject_Add()`` ensures that if the content has
399 already been populated in a previous CMake run, that content will be reused
400 rather than repopulating them again. For the common case where population
401 involves downloading content, the cost of the download is only paid once.
403 An internal global property records when a particular content population
404 request has been processed. If ``FetchContent_Populate()`` is called more
405 than once for the same content name within a configure run, the second call
406 will halt with an error. Projects can and should check whether content
407 population has already been processed with the
408 :command:`FetchContent_GetProperties` command before calling
409 ``FetchContent_Populate()``.
411 ``FetchContent_Populate()`` will set three variables in the scope of the
414 ``<lowercaseName>_POPULATED``
415 This will always be set to ``TRUE`` by the call.
417 ``<lowercaseName>_SOURCE_DIR``
418 The location where the populated content can be found upon return.
420 ``<lowercaseName>_BINARY_DIR``
421 A directory intended for use as a corresponding build directory.
423 The main use case for the ``<lowercaseName>_SOURCE_DIR`` and
424 ``<lowercaseName>_BINARY_DIR`` variables is to call
425 :command:`add_subdirectory` immediately after population:
427 .. code-block:: cmake
429 FetchContent_Populate(FooBar)
430 add_subdirectory(${foobar_SOURCE_DIR} ${foobar_BINARY_DIR})
432 The values of the three variables can also be retrieved from anywhere in the
433 project hierarchy using the :command:`FetchContent_GetProperties` command.
435 The ``FetchContent_Populate()`` command also supports a syntax allowing the
436 content details to be specified directly rather than using any saved
437 details. This is more low-level and use of this form is generally to be
438 avoided in favor of using saved content details as outlined above.
439 Nevertheless, in certain situations it can be useful to invoke the content
440 population as an isolated operation (typically as part of implementing some
441 other higher level feature or when using CMake in script mode):
443 .. code-block:: cmake
445 FetchContent_Populate(
448 [SUBBUILD_DIR <subBuildDir>]
449 [SOURCE_DIR <srcDir>]
450 [BINARY_DIR <binDir>]
454 This form has a number of key differences to that where only ``<name>`` is
457 - All required population details are assumed to have been provided directly
458 in the call to ``FetchContent_Populate()``. Any saved details for
459 ``<name>`` are ignored.
460 - No check is made for whether content for ``<name>`` has already been
462 - No global property is set to record that the population has occurred.
463 - No global properties record the source or binary directories used for the
465 - The ``FETCHCONTENT_FULLY_DISCONNECTED`` and
466 ``FETCHCONTENT_UPDATES_DISCONNECTED`` cache variables are ignored.
468 The ``<lowercaseName>_SOURCE_DIR`` and ``<lowercaseName>_BINARY_DIR``
469 variables are still returned to the caller, but since these locations are
470 not stored as global properties when this form is used, they are only
471 available to the calling scope and below rather than the entire project
472 hierarchy. No ``<lowercaseName>_POPULATED`` variable is set in the caller's
473 scope with this form.
475 The supported options for ``FetchContent_Populate()`` are the same as those
476 for :command:`FetchContent_Declare()`. Those few options shown just
477 above are either specific to ``FetchContent_Populate()`` or their behavior is
478 slightly modified from how :command:`ExternalProject_Add` treats them:
481 The ``QUIET`` option can be given to hide the output associated with
482 populating the specified content. If the population fails, the output will
483 be shown regardless of whether this option was given or not so that the
484 cause of the failure can be diagnosed. The global ``FETCHCONTENT_QUIET``
485 cache variable has no effect on ``FetchContent_Populate()`` calls where the
486 content details are provided directly.
489 The ``SUBBUILD_DIR`` argument can be provided to change the location of the
490 sub-build created to perform the population. The default value is
491 ``${CMAKE_CURRENT_BINARY_DIR}/<lowercaseName>-subbuild`` and it would be
492 unusual to need to override this default. If a relative path is specified,
493 it will be interpreted as relative to :variable:`CMAKE_CURRENT_BINARY_DIR`.
494 This option should not be confused with the ``SOURCE_SUBDIR`` option which
495 only affects the :command:`FetchContent_MakeAvailable` command.
497 ``SOURCE_DIR``, ``BINARY_DIR``
498 The ``SOURCE_DIR`` and ``BINARY_DIR`` arguments are supported by
499 :command:`ExternalProject_Add`, but different default values are used by
500 ``FetchContent_Populate()``. ``SOURCE_DIR`` defaults to
501 ``${CMAKE_CURRENT_BINARY_DIR}/<lowercaseName>-src`` and ``BINARY_DIR``
502 defaults to ``${CMAKE_CURRENT_BINARY_DIR}/<lowercaseName>-build``.
503 If a relative path is specified, it will be interpreted as relative to
504 :variable:`CMAKE_CURRENT_BINARY_DIR`.
506 In addition to the above explicit options, any other unrecognized options are
507 passed through unmodified to :command:`ExternalProject_Add` to perform the
508 download, patch and update steps. The following options are explicitly
509 prohibited (they are disabled by the ``FetchContent_Populate()`` command):
511 - ``CONFIGURE_COMMAND``
513 - ``INSTALL_COMMAND``
516 If using ``FetchContent_Populate()`` within CMake's script mode, be aware
517 that the implementation sets up a sub-build which therefore requires a CMake
518 generator and build tool to be available. If these cannot be found by
519 default, then the :variable:`CMAKE_GENERATOR` and/or
520 :variable:`CMAKE_MAKE_PROGRAM` variables will need to be set appropriately
521 on the command line invoking the script.
523 .. versionadded:: 3.18
524 Added support for the ``DOWNLOAD_NO_EXTRACT`` option.
526 .. command:: FetchContent_GetProperties
528 When using saved content details, a call to
529 :command:`FetchContent_MakeAvailable` or :command:`FetchContent_Populate`
530 records information in global properties which can be queried at any time.
531 This information may include the source and binary directories associated with
532 the content and also whether or not the content population has been processed
533 during the current configure run.
535 .. code-block:: cmake
537 FetchContent_GetProperties(
539 [SOURCE_DIR <srcDirVar>]
540 [BINARY_DIR <binDirVar>]
541 [POPULATED <doneVar>]
544 The ``SOURCE_DIR``, ``BINARY_DIR`` and ``POPULATED`` options can be used to
545 specify which properties should be retrieved. Each option accepts a value
546 which is the name of the variable in which to store that property. Most of
547 the time though, only ``<name>`` is given, in which case the call will then
548 set the same variables as a call to
549 :command:`FetchContent_MakeAvailable(name) <FetchContent_MakeAvailable>` or
550 :command:`FetchContent_Populate(name) <FetchContent_Populate>`.
551 Note that the ``SOURCE_DIR`` and ``BINARY_DIR`` values can be empty if the
552 call is fulfilled by a :ref:`dependency provider <dependency_providers>`.
554 This command is rarely needed when using
555 :command:`FetchContent_MakeAvailable`. It is more commonly used as part of
556 implementing the following pattern with :command:`FetchContent_Populate`,
557 which ensures that the relevant variables will always be defined regardless
558 of whether or not the population has been performed elsewhere in the project
561 .. code-block:: cmake
563 # Check if population has already been performed
564 FetchContent_GetProperties(depname)
565 if(NOT depname_POPULATED)
566 # Fetch the content using previously declared details
567 FetchContent_Populate(depname)
569 # Set custom variables, policies, etc.
572 # Bring the populated content into the build
573 add_subdirectory(${depname_SOURCE_DIR} ${depname_BINARY_DIR})
576 .. command:: FetchContent_SetPopulated
578 .. versionadded:: 3.24
581 This command should only be called by
582 :ref:`dependency providers <dependency_providers>`. Calling it in any
583 other context is unsupported and future CMake versions may halt with a
584 fatal error in such cases.
586 .. code-block:: cmake
588 FetchContent_SetPopulated(
590 [SOURCE_DIR <srcDir>]
591 [BINARY_DIR <binDir>]
594 If a provider command fulfills a ``FETCHCONTENT_MAKEAVAILABLE_SERIAL``
595 request, it must call this function before returning. The ``SOURCE_DIR``
596 and ``BINARY_DIR`` arguments can be used to specify the values that
597 :command:`FetchContent_GetProperties` should return for its corresponding
598 arguments. Only provide ``SOURCE_DIR`` and ``BINARY_DIR`` if they have
599 the same meaning as if they had been populated by the built-in
600 :command:`FetchContent_MakeAvailable` implementation.
606 A number of cache variables can influence the behavior where details from a
607 :command:`FetchContent_Declare` call are used to populate content.
610 All of these variables are intended for the developer to customize behavior.
611 They should not normally be set by the project.
613 .. variable:: FETCHCONTENT_BASE_DIR
615 In most cases, the saved details do not specify any options relating to the
616 directories to use for the internal sub-build, final source and build areas.
617 It is generally best to leave these decisions up to the ``FetchContent``
618 module to handle on the project's behalf. The ``FETCHCONTENT_BASE_DIR``
619 cache variable controls the point under which all content population
620 directories are collected, but in most cases, developers would not need to
621 change this. The default location is ``${CMAKE_BINARY_DIR}/_deps``, but if
622 developers change this value, they should aim to keep the path short and
623 just below the top level of the build tree to avoid running into path
624 length problems on Windows.
626 .. variable:: FETCHCONTENT_QUIET
628 The logging output during population can be quite verbose, making the
629 configure stage quite noisy. This cache option (``ON`` by default) hides
630 all population output unless an error is encountered. If experiencing
631 problems with hung downloads, temporarily switching this option off may
632 help diagnose which content population is causing the issue.
634 .. variable:: FETCHCONTENT_FULLY_DISCONNECTED
636 When this option is enabled, no attempt is made to download or update
637 any content. It is assumed that all content has already been populated in
638 a previous run or the source directories have been pointed at existing
639 contents the developer has provided manually (using options described
640 further below). When the developer knows that no changes have been made to
641 any content details, turning this option ``ON`` can significantly speed up
642 the configure stage. It is ``OFF`` by default.
644 .. variable:: FETCHCONTENT_UPDATES_DISCONNECTED
646 This is a less severe download/update control compared to
647 :variable:`FETCHCONTENT_FULLY_DISCONNECTED`. Instead of bypassing all
648 download and update logic, ``FETCHCONTENT_UPDATES_DISCONNECTED`` only
649 disables the update stage. Therefore, if content has not been downloaded
650 previously, it will still be downloaded when this option is enabled.
651 This can speed up the configure stage, but not as much as
652 :variable:`FETCHCONTENT_FULLY_DISCONNECTED`. It is ``OFF`` by default.
654 .. variable:: FETCHCONTENT_TRY_FIND_PACKAGE_MODE
656 .. versionadded:: 3.24
658 This variable modifies the details that :command:`FetchContent_Declare`
659 records for a given dependency. While it ultimately controls the behavior
660 of :command:`FetchContent_MakeAvailable`, it is the variable's value when
661 :command:`FetchContent_Declare` is called that gets used. It makes no
662 difference what the variable is set to when
663 :command:`FetchContent_MakeAvailable` is called. Since the variable should
664 only be set by the user and not by projects directly, it will typically have
665 the same value throughout anyway, so this distinction is not usually
668 ``FETCHCONTENT_TRY_FIND_PACKAGE_MODE`` ultimately controls whether
669 :command:`FetchContent_MakeAvailable` is allowed to call
670 :command:`find_package` to satisfy a dependency. The variable can be set
671 to one of the following values:
674 :command:`FetchContent_MakeAvailable` will only call
675 :command:`find_package` if the :command:`FetchContent_Declare` call
676 included a ``FIND_PACKAGE_ARGS`` keyword. This is also the default
677 behavior if ``FETCHCONTENT_TRY_FIND_PACKAGE_MODE`` is not set.
680 :command:`find_package` can be called by
681 :command:`FetchContent_MakeAvailable` regardless of whether the
682 :command:`FetchContent_Declare` call included a ``FIND_PACKAGE_ARGS``
683 keyword or not. If no ``FIND_PACKAGE_ARGS`` keyword was given, the
684 behavior will be as though ``FIND_PACKAGE_ARGS`` had been provided,
685 with no additional arguments after it.
688 :command:`FetchContent_MakeAvailable` will not call
689 :command:`find_package`. Any ``FIND_PACKAGE_ARGS`` given to the
690 :command:`FetchContent_Declare` call will be ignored.
692 As a special case, if the :variable:`FETCHCONTENT_SOURCE_DIR_<uppercaseName>`
693 variable has a non-empty value for a dependency, it is assumed that the
694 user is overriding all other methods of making that dependency available.
695 ``FETCHCONTENT_TRY_FIND_PACKAGE_MODE`` will have no effect on that
696 dependency and :command:`FetchContent_MakeAvailable` will not try to call
697 :command:`find_package` for it.
699 In addition to the above, the following variables are also defined for each
702 .. variable:: FETCHCONTENT_SOURCE_DIR_<uppercaseName>
704 If this is set, no download or update steps are performed for the specified
705 content and the ``<lowercaseName>_SOURCE_DIR`` variable returned to the
706 caller is pointed at this location. This gives developers a way to have a
707 separate checkout of the content that they can modify freely without
708 interference from the build. The build simply uses that existing source,
709 but it still defines ``<lowercaseName>_BINARY_DIR`` to point inside its own
710 build area. Developers are strongly encouraged to use this mechanism rather
711 than editing the sources populated in the default location, as changes to
712 sources in the default location can be lost when content population details
713 are changed by the project.
715 .. variable:: FETCHCONTENT_UPDATES_DISCONNECTED_<uppercaseName>
717 This is the per-content equivalent of
718 :variable:`FETCHCONTENT_UPDATES_DISCONNECTED`. If the global option or
719 this option is ``ON``, then updates will be disabled for the named content.
720 Disabling updates for individual content can be useful for content whose
721 details rarely change, while still leaving other frequently changing content
722 with updates enabled.
724 .. _`fetch-content-examples`:
732 This first fairly straightforward example ensures that some popular testing
733 frameworks are available to the main build:
735 .. code-block:: cmake
737 include(FetchContent)
738 FetchContent_Declare(
740 GIT_REPOSITORY https://github.com/google/googletest.git
741 GIT_TAG 703bd9caab50b139428cea1aaff9974ebee5742e # release-1.10.0
743 FetchContent_Declare(
745 GIT_REPOSITORY https://github.com/catchorg/Catch2.git
746 GIT_TAG de6fe184a9ac1a06895cdd1c9b437f0a0bdf14ad # v2.13.4
749 # After the following call, the CMake targets defined by googletest and
750 # Catch2 will be available to the rest of the build
751 FetchContent_MakeAvailable(googletest Catch2)
753 .. _FetchContent-find_package-integration-examples:
755 Integrating With find_package()
756 """""""""""""""""""""""""""""""
758 For the previous example, if the user wanted to try to find ``googletest``
759 and ``Catch2`` via :command:`find_package` first before trying to download
760 and build them from source, they could set the
761 :variable:`FETCHCONTENT_TRY_FIND_PACKAGE_MODE` variable to ``ALWAYS``.
762 This would also affect any other calls to :command:`FetchContent_Declare`
763 throughout the project, which might not be acceptable. The behavior can be
764 enabled for just these two dependencies instead by adding ``FIND_PACKAGE_ARGS``
765 to the declared details and leaving
766 :variable:`FETCHCONTENT_TRY_FIND_PACKAGE_MODE` unset, or set to ``OPT_IN``:
768 .. code-block:: cmake
770 include(FetchContent)
771 FetchContent_Declare(
773 GIT_REPOSITORY https://github.com/google/googletest.git
774 GIT_TAG 703bd9caab50b139428cea1aaff9974ebee5742e # release-1.10.0
775 FIND_PACKAGE_ARGS NAMES gtest
777 FetchContent_Declare(
779 GIT_REPOSITORY https://github.com/catchorg/Catch2.git
780 GIT_TAG de6fe184a9ac1a06895cdd1c9b437f0a0bdf14ad # v2.13.4
784 # This will try calling find_package() first for both dependencies
785 FetchContent_MakeAvailable(googletest Catch2)
787 For ``Catch2``, no additional arguments to :command:`find_package` are needed,
788 so no additional arguments are provided after the ``FIND_PACKAGE_ARGS``
789 keyword. For ``googletest``, its package is more commonly called ``gtest``,
790 so arguments are added to support it being found by that name.
792 If the user wanted to disable :command:`FetchContent_MakeAvailable` from
793 calling :command:`find_package` for any dependency, even if it provided
794 ``FIND_PACKAGE_ARGS`` in its declared details, they could set
795 :variable:`FETCHCONTENT_TRY_FIND_PACKAGE_MODE` to ``NEVER``.
797 If the project wanted to indicate that these two dependencies should be
798 downloaded and built from source and that :command:`find_package` calls
799 should be redirected to use the built dependencies, the
800 ``OVERRIDE_FIND_PACKAGE`` option should be used when declaring the content
803 .. code-block:: cmake
805 include(FetchContent)
806 FetchContent_Declare(
808 GIT_REPOSITORY https://github.com/google/googletest.git
809 GIT_TAG 703bd9caab50b139428cea1aaff9974ebee5742e # release-1.10.0
810 OVERRIDE_FIND_PACKAGE
812 FetchContent_Declare(
814 GIT_REPOSITORY https://github.com/catchorg/Catch2.git
815 GIT_TAG de6fe184a9ac1a06895cdd1c9b437f0a0bdf14ad # v2.13.4
816 OVERRIDE_FIND_PACKAGE
819 # The following will automatically forward through to FetchContent_MakeAvailable()
820 find_package(googletest)
823 CMake provides a FindGTest module which defines some variables that older
824 projects may use instead of linking to the imported targets. To support
825 those cases, we can provide an extras file. In keeping with the
826 "first to define, wins" philosophy of ``FetchContent``, we only write out
827 that file if something else hasn't already done so.
829 .. code-block:: cmake
831 FetchContent_MakeAvailable(googletest)
833 if(NOT EXISTS ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/googletest-extras.cmake AND
834 NOT EXISTS ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/googletestExtras.cmake)
835 file(WRITE ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/googletest-extras.cmake
837 if("${GTEST_LIBRARIES}" STREQUAL "" AND TARGET GTest::gtest)
838 set(GTEST_LIBRARIES GTest::gtest)
840 if("${GTEST_MAIN_LIBRARIES}" STREQUAL "" AND TARGET GTest::gtest_main)
841 set(GTEST_MAIN_LIBRARIES GTest::gtest_main)
843 if("${GTEST_BOTH_LIBRARIES}" STREQUAL "")
844 set(GTEST_BOTH_LIBRARIES ${GTEST_LIBRARIES} ${GTEST_MAIN_LIBRARIES})
849 Projects will also likely be using ``find_package(GTest)`` rather than
850 ``find_package(googletest)``, but it is possible to make use of the
851 :variable:`CMAKE_FIND_PACKAGE_REDIRECTS_DIR` area to pull in the latter as
852 a dependency of the former. This is likely to be sufficient to satisfy
853 a typical ``find_package(GTest)`` call.
855 .. code-block:: cmake
857 FetchContent_MakeAvailable(googletest)
859 if(NOT EXISTS ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/gtest-config.cmake AND
860 NOT EXISTS ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/GTestConfig.cmake)
861 file(WRITE ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/gtest-config.cmake
863 include(CMakeFindDependencyMacro)
864 find_dependency(googletest)
868 if(NOT EXISTS ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/gtest-config-version.cmake AND
869 NOT EXISTS ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/GTestConfigVersion.cmake)
870 file(WRITE ${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/gtest-config-version.cmake
872 include(${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/googletest-config-version.cmake OPTIONAL)
873 if(NOT PACKAGE_VERSION_COMPATIBLE)
874 include(${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/googletestConfigVersion.cmake OPTIONAL)
879 Overriding Where To Find CMakeLists.txt
880 """""""""""""""""""""""""""""""""""""""
882 If the sub-project's ``CMakeLists.txt`` file is not at the top level of its
883 source tree, the ``SOURCE_SUBDIR`` option can be used to tell ``FetchContent``
884 where to find it. The following example shows how to use that option and
885 it also sets a variable which is meaningful to the subproject before pulling
886 it into the main build:
888 .. code-block:: cmake
890 include(FetchContent)
891 FetchContent_Declare(
893 GIT_REPOSITORY https://github.com/protocolbuffers/protobuf.git
894 GIT_TAG ae50d9b9902526efd6c7a1907d09739f959c6297 # v3.15.0
897 set(protobuf_BUILD_TESTS OFF)
898 FetchContent_MakeAvailable(protobuf)
900 Complex Dependency Hierarchies
901 """"""""""""""""""""""""""""""
903 In more complex project hierarchies, the dependency relationships can be more
904 complicated. Consider a hierarchy where ``projA`` is the top level project and
905 it depends directly on projects ``projB`` and ``projC``. Both ``projB`` and
906 ``projC`` can be built standalone and they also both depend on another project
907 ``projD``. ``projB`` additionally depends on ``projE``. This example assumes
908 that all five projects are available on a company git server. The
909 ``CMakeLists.txt`` of each project might have sections like the following:
913 .. code-block:: cmake
915 include(FetchContent)
916 FetchContent_Declare(
918 GIT_REPOSITORY git@mycompany.com:git/projB.git
919 GIT_TAG 4a89dc7e24ff212a7b5167bef7ab079d
921 FetchContent_Declare(
923 GIT_REPOSITORY git@mycompany.com:git/projC.git
924 GIT_TAG 4ad4016bd1d8d5412d135cf8ceea1bb9
926 FetchContent_Declare(
928 GIT_REPOSITORY git@mycompany.com:git/projD.git
929 GIT_TAG origin/integrationBranch
931 FetchContent_Declare(
933 GIT_REPOSITORY git@mycompany.com:git/projE.git
937 # Order is important, see notes in the discussion further below
938 FetchContent_MakeAvailable(projD projB projC)
942 .. code-block:: cmake
944 include(FetchContent)
945 FetchContent_Declare(
947 GIT_REPOSITORY git@mycompany.com:git/projD.git
948 GIT_TAG 20b415f9034bbd2a2e8216e9a5c9e632
950 FetchContent_Declare(
952 GIT_REPOSITORY git@mycompany.com:git/projE.git
953 GIT_TAG 68e20f674a48be38d60e129f600faf7d
956 FetchContent_MakeAvailable(projD projE)
960 .. code-block:: cmake
962 include(FetchContent)
963 FetchContent_Declare(
965 GIT_REPOSITORY git@mycompany.com:git/projD.git
966 GIT_TAG 7d9a17ad2c962aa13e2fbb8043fb6b8a
969 # This particular version of projD requires workarounds
970 FetchContent_GetProperties(projD)
971 if(NOT projd_POPULATED)
972 FetchContent_Populate(projD)
974 # Copy an additional/replacement file into the populated source
975 file(COPY someFile.c DESTINATION ${projd_SOURCE_DIR}/src)
977 add_subdirectory(${projd_SOURCE_DIR} ${projd_BINARY_DIR})
980 A few key points should be noted in the above:
982 - ``projB`` and ``projC`` define different content details for ``projD``,
983 but ``projA`` also defines a set of content details for ``projD``.
984 Because ``projA`` will define them first, the details from ``projB`` and
985 ``projC`` will not be used. The override details defined by ``projA``
986 are not required to match either of those from ``projB`` or ``projC``, but
987 it is up to the higher level project to ensure that the details it does
988 define still make sense for the child projects.
989 - In the ``projA`` call to :command:`FetchContent_MakeAvailable`, ``projD``
990 is listed ahead of ``projB`` and ``projC`` to ensure that ``projA`` is in
991 control of how ``projD`` is populated.
992 - While ``projA`` defines content details for ``projE``, it does not need
993 to explicitly call ``FetchContent_MakeAvailable(projE)`` or
994 ``FetchContent_Populate(projD)`` itself. Instead, it leaves that to the
995 child ``projB``. For higher level projects, it is often enough to just
996 define the override content details and leave the actual population to the
997 child projects. This saves repeating the same thing at each level of the
998 project hierarchy unnecessarily.
1000 Populating Content Without Adding It To The Build
1001 """""""""""""""""""""""""""""""""""""""""""""""""
1003 Projects don't always need to add the populated content to the build.
1004 Sometimes the project just wants to make the downloaded content available at
1005 a predictable location. The next example ensures that a set of standard
1006 company toolchain files (and potentially even the toolchain binaries
1007 themselves) is available early enough to be used for that same build.
1009 .. code-block:: cmake
1011 cmake_minimum_required(VERSION 3.14)
1013 include(FetchContent)
1014 FetchContent_Declare(
1016 URL https://intranet.mycompany.com//toolchains_1.3.2.tar.gz
1018 FetchContent_MakeAvailable(mycom_toolchains)
1020 project(CrossCompileExample)
1022 The project could be configured to use one of the downloaded toolchains like
1025 .. code-block:: shell
1027 cmake -DCMAKE_TOOLCHAIN_FILE=_deps/mycom_toolchains-src/toolchain_arm.cmake /path/to/src
1029 When CMake processes the ``CMakeLists.txt`` file, it will download and unpack
1030 the tarball into ``_deps/mycompany_toolchains-src`` relative to the build
1031 directory. The :variable:`CMAKE_TOOLCHAIN_FILE` variable is not used until
1032 the :command:`project` command is reached, at which point CMake looks for the
1033 named toolchain file relative to the build directory. Because the tarball has
1034 already been downloaded and unpacked by then, the toolchain file will be in
1035 place, even the very first time that ``cmake`` is run in the build directory.
1037 Populating Content In CMake Script Mode
1038 """""""""""""""""""""""""""""""""""""""
1040 This last example demonstrates how one might download and unpack a
1041 firmware tarball using CMake's :manual:`script mode <cmake(1)>`. The call to
1042 :command:`FetchContent_Populate` specifies all the content details and the
1043 unpacked firmware will be placed in a ``firmware`` directory below the
1044 current working directory.
1046 *getFirmware.cmake*:
1048 .. code-block:: cmake
1050 # NOTE: Intended to be run in script mode with cmake -P
1051 include(FetchContent)
1052 FetchContent_Populate(
1054 URL https://mycompany.com/assets/firmware-1.23-arm.tar.gz
1055 URL_HASH MD5=68247684da89b608d466253762b0ff11
1059 #]=======================================================================]
1061 #=======================================================================
1062 # Recording and retrieving content details for later population
1063 #=======================================================================
1065 # Internal use, projects must not call this directly. It is
1066 # intended for use by FetchContent_Declare() only.
1068 # Sets a content-specific global property (not meant for use
1069 # outside of functions defined here in this file) which can later
1070 # be retrieved using __FetchContent_getSavedDetails() with just the
1071 # same content name. If there is already a value stored in the
1072 # property, it is left unchanged and this call has no effect.
1073 # This allows parent projects to define the content details,
1074 # overriding anything a child project may try to set (properties
1075 # are not cached between runs, so the first thing to set it in a
1076 # build will be in control).
1077 function(__FetchContent_declareDetails contentName)
1079 string(TOLOWER ${contentName} contentNameLower)
1080 set(savedDetailsPropertyName "_FetchContent_${contentNameLower}_savedDetails")
1081 get_property(alreadyDefined GLOBAL PROPERTY ${savedDetailsPropertyName} DEFINED)
1086 if("${FETCHCONTENT_TRY_FIND_PACKAGE_MODE}" STREQUAL "ALWAYS")
1087 set(__tryFindPackage TRUE)
1088 set(__tryFindPackageAllowed TRUE)
1089 elseif("${FETCHCONTENT_TRY_FIND_PACKAGE_MODE}" STREQUAL "NEVER")
1090 set(__tryFindPackage FALSE)
1091 set(__tryFindPackageAllowed FALSE)
1092 elseif("${FETCHCONTENT_TRY_FIND_PACKAGE_MODE}" STREQUAL "OPT_IN" OR
1093 NOT DEFINED FETCHCONTENT_TRY_FIND_PACKAGE_MODE)
1094 set(__tryFindPackage FALSE)
1095 set(__tryFindPackageAllowed TRUE)
1098 "Unsupported value for FETCHCONTENT_TRY_FIND_PACKAGE_MODE: "
1099 "${FETCHCONTENT_TRY_FIND_PACKAGE_MODE}"
1104 set(__findPackageArgs)
1105 set(__sawQuietKeyword NO)
1106 set(__sawGlobalKeyword NO)
1107 foreach(__item IN LISTS ARGN)
1108 if(DEFINED __findPackageArgs)
1109 # All remaining args are for find_package()
1110 string(APPEND __findPackageArgs " [==[${__item}]==]")
1111 if(__item STREQUAL "QUIET")
1112 set(__sawQuietKeyword YES)
1113 elseif(__item STREQUAL "GLOBAL")
1114 set(__sawGlobalKeyword YES)
1119 # Still processing non-find_package() args
1120 if(__item STREQUAL "FIND_PACKAGE_ARGS")
1121 if(__tryFindPackageAllowed)
1122 set(__tryFindPackage TRUE)
1124 # All arguments after this keyword are for find_package(). Define the
1125 # variable but with an empty value initially. This allows us to check
1126 # at the start of the loop whether to store remaining items in this
1127 # variable or not. Note that there could be no more args, which is still
1128 # a valid case because we automatically provide ${contentName} as the
1129 # package name and there may not need to be any further arguments.
1130 set(__findPackageArgs "")
1131 continue() # Don't store this item
1132 elseif(__item STREQUAL "OVERRIDE_FIND_PACKAGE")
1133 set(__tryFindPackageAllowed FALSE)
1134 # Define a separate dedicated property for find_package() to check
1135 # in its implementation. This will be a placeholder until FetchContent
1136 # actually does the population. After that, we will have created a
1137 # stand-in config file that find_package() will pick up instead.
1138 set(propertyName "_FetchContent_${contentNameLower}_override_find_package")
1139 define_property(GLOBAL PROPERTY ${propertyName})
1140 set_property(GLOBAL PROPERTY ${propertyName} TRUE)
1143 string(APPEND __cmdArgs " [==[${__item}]==]")
1146 define_property(GLOBAL PROPERTY ${savedDetailsPropertyName})
1147 cmake_language(EVAL CODE
1148 "set_property(GLOBAL PROPERTY ${savedDetailsPropertyName} ${__cmdArgs})"
1151 if(__tryFindPackage AND __tryFindPackageAllowed)
1152 set(propertyName "_FetchContent_${contentNameLower}_find_package_args")
1153 define_property(GLOBAL PROPERTY ${propertyName})
1154 if(NOT __sawQuietKeyword)
1155 list(INSERT __findPackageArgs 0 QUIET)
1157 if(CMAKE_FIND_PACKAGE_TARGETS_GLOBAL AND NOT __sawGlobalKeyword)
1158 list(APPEND __findPackageArgs GLOBAL)
1160 cmake_language(EVAL CODE
1161 "set_property(GLOBAL PROPERTY ${propertyName} ${__findPackageArgs})"
1168 # Internal use, projects must not call this directly. It is
1169 # intended for use by the FetchContent_Declare() function.
1171 # Retrieves details saved for the specified content in an
1172 # earlier call to __FetchContent_declareDetails().
1173 function(__FetchContent_getSavedDetails contentName outVar)
1175 string(TOLOWER ${contentName} contentNameLower)
1176 set(propertyName "_FetchContent_${contentNameLower}_savedDetails")
1177 get_property(alreadyDefined GLOBAL PROPERTY ${propertyName} DEFINED)
1178 if(NOT alreadyDefined)
1179 message(FATAL_ERROR "No content details recorded for ${contentName}")
1181 get_property(propertyValue GLOBAL PROPERTY ${propertyName})
1182 set(${outVar} "${propertyValue}" PARENT_SCOPE)
1187 # Saves population details of the content, sets defaults for the
1188 # SOURCE_DIR and BUILD_DIR.
1189 function(FetchContent_Declare contentName)
1191 # Always check this even if we won't save these details.
1192 # This helps projects catch errors earlier.
1193 # Avoid using if(... IN_LIST ...) so we don't have to alter policy settings
1194 list(FIND ARGN OVERRIDE_FIND_PACKAGE index_OVERRIDE_FIND_PACKAGE)
1195 list(FIND ARGN FIND_PACKAGE_ARGS index_FIND_PACKAGE_ARGS)
1196 if(index_OVERRIDE_FIND_PACKAGE GREATER_EQUAL 0 AND
1197 index_FIND_PACKAGE_ARGS GREATER_EQUAL 0)
1199 "Cannot specify both OVERRIDE_FIND_PACKAGE and FIND_PACKAGE_ARGS "
1200 "when declaring details for ${contentName}"
1204 # Because we are only looking for a subset of the supported keywords, we
1205 # cannot check for multi-value arguments with this method. We will have to
1206 # handle the URL keyword differently.
1210 DOWNLOAD_EXTRACT_TIMESTAMP
1215 cmake_parse_arguments(PARSE_ARGV 1 ARG "" "${oneValueArgs}" "")
1217 string(TOLOWER ${contentName} contentNameLower)
1219 if(NOT ARG_BINARY_DIR)
1220 set(ARG_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/${contentNameLower}-build")
1223 if(NOT ARG_SOURCE_DIR)
1224 set(ARG_SOURCE_DIR "${FETCHCONTENT_BASE_DIR}/${contentNameLower}-src")
1227 if(ARG_SVN_REPOSITORY)
1228 # Add a hash of the svn repository URL to the source dir. This works
1229 # around the problem where if the URL changes, the download would
1230 # fail because it tries to checkout/update rather than switch the
1231 # old URL to the new one. We limit the hash to the first 7 characters
1232 # so that the source path doesn't get overly long (which can be a
1233 # problem on windows due to path length limits).
1234 string(SHA1 urlSHA ${ARG_SVN_REPOSITORY})
1235 string(SUBSTRING ${urlSHA} 0 7 urlSHA)
1236 string(APPEND ARG_SOURCE_DIR "-${urlSHA}")
1239 # The ExternalProject_Add() call in the sub-build won't see the CMP0135
1240 # policy setting of our caller. Work out if that policy will be needed and
1241 # explicitly set the relevant option if not already provided. The condition
1242 # here is essentially an abbreviated version of the logic in
1243 # ExternalProject's _ep_add_download_command() function.
1244 if(NOT ARG_DOWNLOAD_NO_EXTRACT AND
1245 NOT DEFINED ARG_DOWNLOAD_EXTRACT_TIMESTAMP)
1246 list(FIND ARGN URL urlIndex)
1247 if(urlIndex GREATER_EQUAL 0)
1248 math(EXPR urlIndex "${urlIndex} + 1")
1249 list(LENGTH ARGN numArgs)
1250 if(urlIndex GREATER_EQUAL numArgs)
1252 "URL keyword needs to be followed by at least one URL"
1255 # If we have multiple URLs, none of them are allowed to be local paths.
1256 # Therefore, we can test just the first URL, and if it is non-local, so
1257 # will be the others if there are more.
1258 list(GET ARGN ${urlIndex} firstUrl)
1259 if(NOT IS_DIRECTORY "${firstUrl}")
1260 cmake_policy(GET CMP0135 _FETCHCONTENT_CMP0135
1261 PARENT_SCOPE # undocumented, do not use outside of CMake
1263 if(_FETCHCONTENT_CMP0135 STREQUAL "")
1264 message(AUTHOR_WARNING
1265 "The DOWNLOAD_EXTRACT_TIMESTAMP option was not given and policy "
1266 "CMP0135 is not set. The policy's OLD behavior will be used. "
1267 "When using a URL download, the timestamps of extracted files "
1268 "should preferably be that of the time of extraction, otherwise "
1269 "code that depends on the extracted contents might not be "
1270 "rebuilt if the URL changes. The OLD behavior preserves the "
1271 "timestamps from the archive instead, but this is usually not "
1272 "what you want. Update your project to the NEW behavior or "
1273 "specify the DOWNLOAD_EXTRACT_TIMESTAMP option with a value of "
1274 "true to avoid this robustness issue."
1276 set(ARG_DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
1277 elseif(_FETCHCONTENT_CMP0135 STREQUAL "NEW")
1278 set(ARG_DOWNLOAD_EXTRACT_TIMESTAMP FALSE)
1280 set(ARG_DOWNLOAD_EXTRACT_TIMESTAMP TRUE)
1286 # Add back in the keyword args we pulled out and potentially tweaked/added
1287 foreach(key IN LISTS oneValueArgs)
1288 if(DEFINED ARG_${key})
1289 list(PREPEND ARG_UNPARSED_ARGUMENTS ${key} "${ARG_${key}}")
1294 foreach(__item IN LISTS ARG_UNPARSED_ARGUMENTS)
1295 string(APPEND __argsQuoted " [==[${__item}]==]")
1297 cmake_language(EVAL CODE
1298 "__FetchContent_declareDetails(${contentNameLower} ${__argsQuoted})"
1304 #=======================================================================
1305 # Set/get whether the specified content has been populated yet.
1306 # The setter also records the source and binary dirs used.
1307 #=======================================================================
1309 # Semi-internal use. Projects must not call this directly. Dependency
1310 # providers must call it if they satisfy a request made with the
1311 # FETCHCONTENT_MAKEAVAILABLE_SERIAL method (that is the only permitted
1312 # place to call it outside of the FetchContent module).
1313 function(FetchContent_SetPopulated contentName)
1315 cmake_parse_arguments(PARSE_ARGV 1 arg
1317 "SOURCE_DIR;BINARY_DIR"
1320 if(NOT "${arg_UNPARSED_ARGUMENTS}" STREQUAL "")
1321 message(FATAL_ERROR "Unsupported arguments: ${arg_UNPARSED_ARGUMENTS}")
1324 string(TOLOWER ${contentName} contentNameLower)
1325 set(prefix "_FetchContent_${contentNameLower}")
1327 set(propertyName "${prefix}_sourceDir")
1328 define_property(GLOBAL PROPERTY ${propertyName})
1329 if("${arg_SOURCE_DIR}" STREQUAL "")
1330 # Don't discard a previously provided SOURCE_DIR
1331 get_property(arg_SOURCE_DIR GLOBAL PROPERTY ${propertyName})
1333 set_property(GLOBAL PROPERTY ${propertyName} "${arg_SOURCE_DIR}")
1335 set(propertyName "${prefix}_binaryDir")
1336 define_property(GLOBAL PROPERTY ${propertyName})
1337 if("${arg_BINARY_DIR}" STREQUAL "")
1338 # Don't discard a previously provided BINARY_DIR
1339 get_property(arg_BINARY_DIR GLOBAL PROPERTY ${propertyName})
1341 set_property(GLOBAL PROPERTY ${propertyName} "${arg_BINARY_DIR}")
1343 set(propertyName "${prefix}_populated")
1344 define_property(GLOBAL PROPERTY ${propertyName})
1345 set_property(GLOBAL PROPERTY ${propertyName} TRUE)
1350 # Set variables in the calling scope for any of the retrievable
1351 # properties. If no specific properties are requested, variables
1352 # will be set for all retrievable properties.
1354 # This function is intended to also be used by projects as the canonical
1355 # way to detect whether they should call FetchContent_Populate()
1356 # and pull the populated source into the build with add_subdirectory(),
1357 # if they are using the populated content in that way.
1358 function(FetchContent_GetProperties contentName)
1360 string(TOLOWER ${contentName} contentNameLower)
1363 set(oneValueArgs SOURCE_DIR BINARY_DIR POPULATED)
1364 set(multiValueArgs "")
1366 cmake_parse_arguments(ARG "${options}" "${oneValueArgs}" "${multiValueArgs}" ${ARGN})
1368 if(NOT ARG_SOURCE_DIR AND
1369 NOT ARG_BINARY_DIR AND
1371 # No specific properties requested, provide them all
1372 set(ARG_SOURCE_DIR ${contentNameLower}_SOURCE_DIR)
1373 set(ARG_BINARY_DIR ${contentNameLower}_BINARY_DIR)
1374 set(ARG_POPULATED ${contentNameLower}_POPULATED)
1377 set(prefix "_FetchContent_${contentNameLower}")
1380 set(propertyName "${prefix}_sourceDir")
1381 get_property(value GLOBAL PROPERTY ${propertyName})
1383 set(${ARG_SOURCE_DIR} ${value} PARENT_SCOPE)
1388 set(propertyName "${prefix}_binaryDir")
1389 get_property(value GLOBAL PROPERTY ${propertyName})
1391 set(${ARG_BINARY_DIR} ${value} PARENT_SCOPE)
1396 set(propertyName "${prefix}_populated")
1397 get_property(value GLOBAL PROPERTY ${propertyName} DEFINED)
1398 set(${ARG_POPULATED} ${value} PARENT_SCOPE)
1404 #=======================================================================
1405 # Performing the population
1406 #=======================================================================
1408 # The value of contentName will always have been lowercased by the caller.
1409 # All other arguments are assumed to be options that are understood by
1410 # ExternalProject_Add(), except for QUIET and SUBBUILD_DIR.
1411 function(__FetchContent_directPopulate contentName)
1420 # We need special processing if DOWNLOAD_NO_EXTRACT is true
1422 # Prevent the following from being passed through
1427 # We force these to be ON since we are always executing serially
1428 # and we want all steps to have access to the terminal in case they
1429 # need input from the command line (e.g. ask for a private key password)
1430 # or they want to provide timely progress. We silently absorb and
1431 # discard these if they are set by the caller.
1432 USES_TERMINAL_DOWNLOAD
1433 USES_TERMINAL_UPDATE
1436 set(multiValueArgs "")
1438 cmake_parse_arguments(PARSE_ARGV 1 ARG
1439 "${options}" "${oneValueArgs}" "${multiValueArgs}")
1441 if(NOT ARG_SUBBUILD_DIR)
1442 message(FATAL_ERROR "Internal error: SUBBUILD_DIR not set")
1443 elseif(NOT IS_ABSOLUTE "${ARG_SUBBUILD_DIR}")
1444 set(ARG_SUBBUILD_DIR "${CMAKE_CURRENT_BINARY_DIR}/${ARG_SUBBUILD_DIR}")
1447 if(NOT ARG_SOURCE_DIR)
1448 message(FATAL_ERROR "Internal error: SOURCE_DIR not set")
1449 elseif(NOT IS_ABSOLUTE "${ARG_SOURCE_DIR}")
1450 set(ARG_SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}/${ARG_SOURCE_DIR}")
1453 if(NOT ARG_BINARY_DIR)
1454 message(FATAL_ERROR "Internal error: BINARY_DIR not set")
1455 elseif(NOT IS_ABSOLUTE "${ARG_BINARY_DIR}")
1456 set(ARG_BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/${ARG_BINARY_DIR}")
1459 # Ensure the caller can know where to find the source and build directories
1460 # with some convenient variables. Doing this here ensures the caller sees
1461 # the correct result in the case where the default values are overridden by
1462 # the content details set by the project.
1463 set(${contentName}_SOURCE_DIR "${ARG_SOURCE_DIR}" PARENT_SCOPE)
1464 set(${contentName}_BINARY_DIR "${ARG_BINARY_DIR}" PARENT_SCOPE)
1466 # The unparsed arguments may contain spaces, so build up ARG_EXTRA
1467 # in such a way that it correctly substitutes into the generated
1468 # CMakeLists.txt file with each argument quoted.
1470 foreach(arg IN LISTS ARG_UNPARSED_ARGUMENTS)
1471 set(ARG_EXTRA "${ARG_EXTRA} \"${arg}\"")
1474 if(ARG_DOWNLOAD_NO_EXTRACT)
1475 set(ARG_EXTRA "${ARG_EXTRA} DOWNLOAD_NO_EXTRACT YES")
1476 set(__FETCHCONTENT_COPY_FILE
1478 ExternalProject_Get_Property(${contentName}-populate DOWNLOADED_FILE)
1479 get_filename_component(dlFileName \"\${DOWNLOADED_FILE}\" NAME)
1481 ExternalProject_Add_Step(${contentName}-populate copyfile
1482 COMMAND \"${CMAKE_COMMAND}\" -E copy_if_different
1483 \"<DOWNLOADED_FILE>\" \"${ARG_SOURCE_DIR}\"
1486 BYPRODUCTS \"${ARG_SOURCE_DIR}/\${dlFileName}\"
1487 COMMENT \"Copying file to SOURCE_DIR\"
1491 unset(__FETCHCONTENT_COPY_FILE)
1494 # Hide output if requested, but save it to a variable in case there's an
1495 # error so we can show the output upon failure. When not quiet, don't
1496 # capture the output to a variable because the user may want to see the
1497 # output as it happens (e.g. progress during long downloads). Combine both
1498 # stdout and stderr in the one capture variable so the output stays in order.
1501 OUTPUT_VARIABLE capturedOutput
1502 ERROR_VARIABLE capturedOutput
1507 message(STATUS "Populating ${contentName}")
1511 set(subCMakeOpts "-G${CMAKE_GENERATOR}")
1512 if(CMAKE_GENERATOR_PLATFORM)
1513 list(APPEND subCMakeOpts "-A${CMAKE_GENERATOR_PLATFORM}")
1515 if(CMAKE_GENERATOR_TOOLSET)
1516 list(APPEND subCMakeOpts "-T${CMAKE_GENERATOR_TOOLSET}")
1519 if(CMAKE_MAKE_PROGRAM)
1520 list(APPEND subCMakeOpts "-DCMAKE_MAKE_PROGRAM:FILEPATH=${CMAKE_MAKE_PROGRAM}")
1523 # Override the sub-build's configuration types for multi-config generators.
1524 # This ensures we are not affected by any custom setting from the project
1525 # and can always request a known configuration further below.
1526 get_property(is_multi_config GLOBAL PROPERTY GENERATOR_IS_MULTI_CONFIG)
1528 list(APPEND subCMakeOpts "-DCMAKE_CONFIGURATION_TYPES:STRING=Debug")
1532 # Likely we've been invoked via CMake's script mode where no
1533 # generator is set (and hence CMAKE_MAKE_PROGRAM could not be
1534 # trusted even if provided). We will have to rely on being
1535 # able to find the default generator and build tool.
1539 set(__FETCHCONTENT_CACHED_INFO "")
1540 set(__passthrough_vars
1541 CMAKE_EP_GIT_REMOTE_UPDATE_STRATEGY
1547 foreach(var IN LISTS __passthrough_vars)
1549 # Embed directly in the generated CMakeLists.txt file to avoid making
1550 # the cmake command line excessively long. It also makes debugging and
1552 string(APPEND __FETCHCONTENT_CACHED_INFO "set(${var} [==[${${var}}]==])\n")
1556 # Avoid using if(... IN_LIST ...) so we don't have to alter policy settings
1557 list(FIND ARG_UNPARSED_ARGUMENTS GIT_REPOSITORY indexResult)
1558 if(indexResult GREATER_EQUAL 0)
1559 find_package(Git QUIET)
1560 string(APPEND __FETCHCONTENT_CACHED_INFO "
1561 # Pass through things we've already detected in the main project to avoid
1562 # paying the cost of redetecting them again in ExternalProject_Add()
1563 set(GIT_EXECUTABLE [==[${GIT_EXECUTABLE}]==])
1564 set(GIT_VERSION_STRING [==[${GIT_VERSION_STRING}]==])
1565 set_property(GLOBAL PROPERTY _CMAKE_FindGit_GIT_EXECUTABLE_VERSION
1566 [==[${GIT_EXECUTABLE};${GIT_VERSION_STRING}]==]
1571 # Create and build a separate CMake project to carry out the population.
1572 # If we've already previously done these steps, they will not cause
1573 # anything to be updated, so extra rebuilds of the project won't occur.
1574 # Make sure to pass through CMAKE_MAKE_PROGRAM in case the main project
1575 # has this set to something not findable on the PATH. We also ensured above
1576 # that the Debug config will be defined for multi-config generators.
1577 configure_file("${CMAKE_CURRENT_FUNCTION_LIST_DIR}/FetchContent/CMakeLists.cmake.in"
1578 "${ARG_SUBBUILD_DIR}/CMakeLists.txt")
1580 COMMAND ${CMAKE_COMMAND} ${subCMakeOpts} .
1581 RESULT_VARIABLE result
1583 WORKING_DIRECTORY "${ARG_SUBBUILD_DIR}"
1587 message("${capturedOutput}")
1589 message(FATAL_ERROR "CMake step for ${contentName} failed: ${result}")
1592 COMMAND ${CMAKE_COMMAND} --build . --config Debug
1593 RESULT_VARIABLE result
1595 WORKING_DIRECTORY "${ARG_SUBBUILD_DIR}"
1599 message("${capturedOutput}")
1601 message(FATAL_ERROR "Build step for ${contentName} failed: ${result}")
1607 option(FETCHCONTENT_FULLY_DISCONNECTED "Disables all attempts to download or update content and assumes source dirs already exist")
1608 option(FETCHCONTENT_UPDATES_DISCONNECTED "Enables UPDATE_DISCONNECTED behavior for all content population")
1609 option(FETCHCONTENT_QUIET "Enables QUIET option for all content population" ON)
1610 set(FETCHCONTENT_BASE_DIR "${CMAKE_BINARY_DIR}/_deps" CACHE PATH "Directory under which to collect all populated content")
1612 # Populate the specified content using details stored from
1613 # an earlier call to FetchContent_Declare().
1614 function(FetchContent_Populate contentName)
1617 message(FATAL_ERROR "Empty contentName not allowed for FetchContent_Populate()")
1620 string(TOLOWER ${contentName} contentNameLower)
1623 # This is the direct population form with details fully specified
1624 # as part of the call, so we already have everything we need
1625 __FetchContent_directPopulate(
1627 SUBBUILD_DIR "${CMAKE_CURRENT_BINARY_DIR}/${contentNameLower}-subbuild"
1628 SOURCE_DIR "${CMAKE_CURRENT_BINARY_DIR}/${contentNameLower}-src"
1629 BINARY_DIR "${CMAKE_CURRENT_BINARY_DIR}/${contentNameLower}-build"
1630 ${ARGN} # Could override any of the above ..._DIR variables
1633 # Pass source and binary dir variables back to the caller
1634 set(${contentNameLower}_SOURCE_DIR "${${contentNameLower}_SOURCE_DIR}" PARENT_SCOPE)
1635 set(${contentNameLower}_BINARY_DIR "${${contentNameLower}_BINARY_DIR}" PARENT_SCOPE)
1637 # Don't set global properties, or record that we did this population, since
1638 # this was a direct call outside of the normal declared details form.
1639 # We only want to save values in the global properties for content that
1640 # honors the hierarchical details mechanism so that projects are not
1641 # robbed of the ability to override details set in nested projects.
1645 # No details provided, so assume they were saved from an earlier call
1646 # to FetchContent_Declare(). Do a check that we haven't already
1647 # populated this content before in case the caller forgot to check.
1648 FetchContent_GetProperties(${contentName})
1649 if(${contentNameLower}_POPULATED)
1650 if("${${contentNameLower}_SOURCE_DIR}" STREQUAL "")
1652 "Content ${contentName} already populated by find_package() or a "
1653 "dependency provider"
1657 "Content ${contentName} already populated in ${${contentNameLower}_SOURCE_DIR}"
1662 __FetchContent_getSavedDetails(${contentName} contentDetails)
1663 if("${contentDetails}" STREQUAL "")
1664 message(FATAL_ERROR "No details have been set for content: ${contentName}")
1667 string(TOUPPER ${contentName} contentNameUpper)
1668 set(FETCHCONTENT_SOURCE_DIR_${contentNameUpper}
1669 "${FETCHCONTENT_SOURCE_DIR_${contentNameUpper}}"
1670 CACHE PATH "When not empty, overrides where to find pre-populated content for ${contentName}")
1672 if(FETCHCONTENT_SOURCE_DIR_${contentNameUpper})
1673 # The source directory has been explicitly provided in the cache,
1674 # so no population is required. The build directory may still be specified
1675 # by the declared details though.
1677 if(NOT IS_ABSOLUTE "${FETCHCONTENT_SOURCE_DIR_${contentNameUpper}}")
1678 # Don't check this directory because we don't know what location it is
1679 # expected to be relative to. We can't make this a hard error for backward
1680 # compatibility reasons.
1681 message(WARNING "Relative source directory specified. This is not safe, "
1682 "as it depends on the calling directory scope.\n"
1683 " FETCHCONTENT_SOURCE_DIR_${contentNameUpper} --> ${FETCHCONTENT_SOURCE_DIR_${contentNameUpper}}")
1684 elseif(NOT EXISTS "${FETCHCONTENT_SOURCE_DIR_${contentNameUpper}}")
1685 message(FATAL_ERROR "Manually specified source directory is missing:\n"
1686 " FETCHCONTENT_SOURCE_DIR_${contentNameUpper} --> ${FETCHCONTENT_SOURCE_DIR_${contentNameUpper}}")
1689 set(${contentNameLower}_SOURCE_DIR "${FETCHCONTENT_SOURCE_DIR_${contentNameUpper}}")
1691 cmake_parse_arguments(savedDetails "" "BINARY_DIR" "" ${contentDetails})
1693 if(savedDetails_BINARY_DIR)
1694 set(${contentNameLower}_BINARY_DIR ${savedDetails_BINARY_DIR})
1696 set(${contentNameLower}_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/${contentNameLower}-build")
1699 elseif(FETCHCONTENT_FULLY_DISCONNECTED)
1700 # Bypass population and assume source is already there from a previous run.
1701 # Declared details may override the default source or build directories.
1703 cmake_parse_arguments(savedDetails "" "SOURCE_DIR;BINARY_DIR" "" ${contentDetails})
1705 if(savedDetails_SOURCE_DIR)
1706 set(${contentNameLower}_SOURCE_DIR ${savedDetails_SOURCE_DIR})
1708 set(${contentNameLower}_SOURCE_DIR "${FETCHCONTENT_BASE_DIR}/${contentNameLower}-src")
1711 if(savedDetails_BINARY_DIR)
1712 set(${contentNameLower}_BINARY_DIR ${savedDetails_BINARY_DIR})
1714 set(${contentNameLower}_BINARY_DIR "${FETCHCONTENT_BASE_DIR}/${contentNameLower}-build")
1718 # Support both a global "disconnect all updates" and a per-content
1719 # update test (either one being set disables updates for this content).
1720 option(FETCHCONTENT_UPDATES_DISCONNECTED_${contentNameUpper}
1721 "Enables UPDATE_DISCONNECTED behavior just for population of ${contentName}")
1722 if(FETCHCONTENT_UPDATES_DISCONNECTED OR
1723 FETCHCONTENT_UPDATES_DISCONNECTED_${contentNameUpper})
1724 set(disconnectUpdates True)
1726 set(disconnectUpdates False)
1729 if(FETCHCONTENT_QUIET)
1730 set(quietFlag QUIET)
1735 set(__detailsQuoted)
1736 foreach(__item IN LISTS contentDetails)
1737 if(NOT __item STREQUAL "OVERRIDE_FIND_PACKAGE")
1738 string(APPEND __detailsQuoted " [==[${__item}]==]")
1741 cmake_language(EVAL CODE "
1742 __FetchContent_directPopulate(
1745 UPDATE_DISCONNECTED ${disconnectUpdates}
1746 SUBBUILD_DIR \"${FETCHCONTENT_BASE_DIR}/${contentNameLower}-subbuild\"
1747 SOURCE_DIR \"${FETCHCONTENT_BASE_DIR}/${contentNameLower}-src\"
1748 BINARY_DIR \"${FETCHCONTENT_BASE_DIR}/${contentNameLower}-build\"
1749 # Put the saved details last so they can override any of the
1750 # the options we set above (this can include SOURCE_DIR or
1757 FetchContent_SetPopulated(
1759 SOURCE_DIR "${${contentNameLower}_SOURCE_DIR}"
1760 BINARY_DIR "${${contentNameLower}_BINARY_DIR}"
1763 # Pass variables back to the caller. The variables passed back here
1764 # must match what FetchContent_GetProperties() sets when it is called
1765 # with just the content name.
1766 set(${contentNameLower}_SOURCE_DIR "${${contentNameLower}_SOURCE_DIR}" PARENT_SCOPE)
1767 set(${contentNameLower}_BINARY_DIR "${${contentNameLower}_BINARY_DIR}" PARENT_SCOPE)
1768 set(${contentNameLower}_POPULATED True PARENT_SCOPE)
1772 function(__FetchContent_setupFindPackageRedirection contentName)
1774 __FetchContent_getSavedDetails(${contentName} contentDetails)
1776 string(TOLOWER ${contentName} contentNameLower)
1777 get_property(wantFindPackage GLOBAL PROPERTY
1778 _FetchContent_${contentNameLower}_find_package_args
1782 # Avoid using if(... IN_LIST ...) so we don't have to alter policy settings
1783 list(FIND contentDetails OVERRIDE_FIND_PACKAGE indexResult)
1784 if(NOT wantFindPackage AND indexResult EQUAL -1)
1785 # No find_package() redirection allowed
1789 # We write out dep-config.cmake and dep-config-version.cmake file name
1790 # forms here because they are forced to lowercase. FetchContent
1791 # dependency names are case-insensitive, but find_package() config files
1792 # are only case-insensitive for the -config and -config-version forms,
1793 # not the Config and ConfigVersion forms.
1794 set(inFileDir ${CMAKE_CURRENT_FUNCTION_LIST_DIR}/FetchContent)
1795 set(configFilePrefix1 "${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/${contentName}Config")
1796 set(configFilePrefix2 "${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}/${contentNameLower}-config")
1797 if(NOT EXISTS "${configFilePrefix1}.cmake" AND
1798 NOT EXISTS "${configFilePrefix2}.cmake")
1799 configure_file(${inFileDir}/package-config.cmake.in
1800 "${configFilePrefix2}.cmake" @ONLY
1803 if(NOT EXISTS "${configFilePrefix1}Version.cmake" AND
1804 NOT EXISTS "${configFilePrefix2}-version.cmake")
1805 configure_file(${inFileDir}/package-config-version.cmake.in
1806 "${configFilePrefix2}-version.cmake" @ONLY
1810 # Now that we've created the redirected package config files, prevent
1811 # find_package() from delegating to FetchContent and let it find these
1812 # config files through its normal processing.
1813 set(propertyName "${prefix}_override_find_package")
1814 set(GLOBAL PROPERTY ${propertyName} FALSE)
1815 set(${contentName}_DIR "${CMAKE_FIND_PACKAGE_REDIRECTS_DIR}"
1816 CACHE INTERNAL "Redirected by FetchContent"
1821 # Arguments are assumed to be the names of dependencies that have been
1822 # declared previously and should be populated. It is not an error if
1823 # any of them have already been populated (they will just be skipped in
1824 # that case). The command is implemented as a macro so that the variables
1825 # defined by the FetchContent_GetProperties() and FetchContent_Populate()
1826 # calls will be available to the caller.
1827 macro(FetchContent_MakeAvailable)
1829 # We must append an item, even if the variable is unset, so prefix its value.
1830 # We will strip that prefix when we pop the value at the end of the macro.
1831 list(APPEND __cmake_fcCurrentVarsStack
1832 "__fcprefix__${CMAKE_VERIFY_INTERFACE_HEADER_SETS}"
1834 set(CMAKE_VERIFY_INTERFACE_HEADER_SETS FALSE)
1836 get_property(__cmake_providerCommand GLOBAL PROPERTY
1837 __FETCHCONTENT_MAKEAVAILABLE_SERIAL_PROVIDER
1839 foreach(__cmake_contentName IN ITEMS ${ARGV})
1840 string(TOLOWER ${__cmake_contentName} __cmake_contentNameLower)
1842 # If user specified FETCHCONTENT_SOURCE_DIR_... for this dependency, that
1843 # overrides everything else and we shouldn't try to use find_package() or
1844 # a dependency provider.
1845 string(TOUPPER ${__cmake_contentName} __cmake_contentNameUpper)
1846 if("${FETCHCONTENT_SOURCE_DIR_${__cmake_contentNameUpper}}" STREQUAL "")
1847 # Dependency provider gets first opportunity, but prevent infinite
1848 # recursion if we are called again for the same thing
1849 if(NOT "${__cmake_providerCommand}" STREQUAL "" AND
1850 NOT DEFINED __cmake_fcProvider_${__cmake_contentNameLower})
1852 "Trying FETCHCONTENT_MAKEAVAILABLE_SERIAL dependency provider for "
1853 "${__cmake_contentName}"
1855 # It's still valid if there are no saved details. The project may have
1856 # been written to assume a dependency provider is always set and will
1857 # provide dependencies without having any declared details for them.
1858 __FetchContent_getSavedDetails(${__cmake_contentName} __cmake_contentDetails)
1859 set(__cmake_providerArgs
1860 "FETCHCONTENT_MAKEAVAILABLE_SERIAL"
1861 "${__cmake_contentName}"
1863 # Empty arguments must be preserved because of things like
1864 # GIT_SUBMODULES (see CMP0097)
1865 foreach(__cmake_item IN LISTS __cmake_contentDetails)
1866 string(APPEND __cmake_providerArgs " [==[${__cmake_item}]==]")
1869 # This property might be defined but empty. As long as it is defined,
1870 # find_package() can be called.
1871 get_property(__cmake_addfpargs GLOBAL PROPERTY
1872 _FetchContent_${contentNameLower}_find_package_args
1875 if(__cmake_addfpargs)
1876 get_property(__cmake_fpargs GLOBAL PROPERTY
1877 _FetchContent_${contentNameLower}_find_package_args
1879 string(APPEND __cmake_providerArgs " FIND_PACKAGE_ARGS")
1880 foreach(__cmake_item IN LISTS __cmake_fpargs)
1881 string(APPEND __cmake_providerArgs " [==[${__cmake_item}]==]")
1885 # Calling the provider could lead to FetchContent_MakeAvailable() being
1886 # called for a nested dependency. That nested call may occur in the
1887 # current variable scope. We have to save and restore the variables we
1889 list(APPEND __cmake_fcCurrentVarsStack
1890 ${__cmake_contentName}
1891 ${__cmake_contentNameLower}
1894 set(__cmake_fcProvider_${__cmake_contentNameLower} YES)
1895 cmake_language(EVAL CODE "${__cmake_providerCommand}(${__cmake_providerArgs})")
1896 unset(__cmake_fcProvider_${__cmake_contentNameLower})
1898 list(POP_BACK __cmake_fcCurrentVarsStack
1899 __cmake_contentNameLower
1903 unset(__cmake_providerArgs)
1904 unset(__cmake_addfpargs)
1905 unset(__cmake_fpargs)
1907 unset(__cmake_contentDetails)
1909 FetchContent_GetProperties(${__cmake_contentName})
1910 if(${__cmake_contentNameLower}_POPULATED)
1915 # Check if we've been asked to try find_package() first, even if we
1916 # have already populated this dependency. If we previously tried to
1917 # use find_package() for this and it succeeded, those things might
1918 # no longer be in scope, so we have to do it again.
1919 get_property(__cmake_haveFpArgs GLOBAL PROPERTY
1920 _FetchContent_${__cmake_contentNameLower}_find_package_args DEFINED
1922 if(__cmake_haveFpArgs)
1923 unset(__cmake_haveFpArgs)
1924 message(VERBOSE "Trying find_package(${__cmake_contentName} ...) before FetchContent")
1925 get_property(__cmake_fpArgs GLOBAL PROPERTY
1926 _FetchContent_${__cmake_contentNameLower}_find_package_args
1929 # This call could lead to FetchContent_MakeAvailable() being called for
1930 # a nested dependency and it may occur in the current variable scope.
1931 # We have to save/restore the variables we need to preserve.
1932 list(APPEND __cmake_fcCurrentNameStack
1933 ${__cmake_contentName}
1934 ${__cmake_contentNameLower}
1936 find_package(${__cmake_contentName} ${__cmake_fpArgs})
1937 list(POP_BACK __cmake_fcCurrentNameStack
1938 __cmake_contentNameLower
1941 unset(__cmake_fpArgs)
1943 if(${__cmake_contentName}_FOUND)
1944 FetchContent_SetPopulated(${__cmake_contentName})
1945 FetchContent_GetProperties(${__cmake_contentName})
1950 unset(__cmake_haveFpArgs)
1953 FetchContent_GetProperties(${__cmake_contentName})
1954 if(NOT ${__cmake_contentNameLower}_POPULATED)
1955 FetchContent_Populate(${__cmake_contentName})
1956 __FetchContent_setupFindPackageRedirection(${__cmake_contentName})
1958 # Only try to call add_subdirectory() if the populated content
1959 # can be treated that way. Protecting the call with the check
1960 # allows this function to be used for projects that just want
1961 # to ensure the content exists, such as to provide content at
1962 # a known location. We check the saved details for an optional
1963 # SOURCE_SUBDIR which can be used in the same way as its meaning
1964 # for ExternalProject. It won't matter if it was passed through
1965 # to the ExternalProject sub-build, since it would have been
1967 set(__cmake_srcdir "${${__cmake_contentNameLower}_SOURCE_DIR}")
1968 __FetchContent_getSavedDetails(${__cmake_contentName} __cmake_contentDetails)
1969 if("${__cmake_contentDetails}" STREQUAL "")
1970 message(FATAL_ERROR "No details have been set for content: ${__cmake_contentName}")
1972 cmake_parse_arguments(__cmake_arg "" "SOURCE_SUBDIR" "" ${__cmake_contentDetails})
1973 if(NOT "${__cmake_arg_SOURCE_SUBDIR}" STREQUAL "")
1974 string(APPEND __cmake_srcdir "/${__cmake_arg_SOURCE_SUBDIR}")
1977 if(EXISTS ${__cmake_srcdir}/CMakeLists.txt)
1978 add_subdirectory(${__cmake_srcdir} ${${__cmake_contentNameLower}_BINARY_DIR})
1981 unset(__cmake_srcdir)
1982 unset(__cmake_contentDetails)
1983 unset(__cmake_arg_SOURCE_SUBDIR)
1987 # Prefix will be "__fcprefix__"
1988 list(POP_BACK __cmake_fcCurrentVarsStack __cmake_original_verify_setting)
1989 string(SUBSTRING "${__cmake_original_verify_setting}"
1990 12 -1 __cmake_original_verify_setting
1992 set(CMAKE_VERIFY_INTERFACE_HEADER_SETS ${__cmake_original_verify_setting})
1994 # clear local variables to prevent leaking into the caller's scope
1995 unset(__cmake_contentName)
1996 unset(__cmake_contentNameLower)
1997 unset(__cmake_contentNameUpper)
1998 unset(__cmake_providerCommand)
1999 unset(__cmake_original_verify_setting)