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576 lines
20 KiB
576 lines
20 KiB
file
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----
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File manipulation command.
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Synopsis
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^^^^^^^^
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.. parsed-literal::
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`Reading`_
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file(`READ`_ <filename> <out-var> [...])
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file(`STRINGS`_ <filename> <out-var> [...])
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file(`\<HASH\> <HASH_>`_ <filename> <out-var>)
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file(`TIMESTAMP`_ <filename> <out-var> [...])
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`Writing`_
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file({`WRITE`_ | `APPEND`_} <filename> <content>...)
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file({`TOUCH`_ | `TOUCH_NOCREATE`_} [<file>...])
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file(`GENERATE`_ OUTPUT <output-file> [...])
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`Filesystem`_
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file({`GLOB`_ | `GLOB_RECURSE`_} <out-var> [...] [<globbing-expr>...])
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file(`RENAME`_ <oldname> <newname>)
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file({`REMOVE`_ | `REMOVE_RECURSE`_ } [<files>...])
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file(`MAKE_DIRECTORY`_ [<dir>...])
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file({`COPY`_ | `INSTALL`_} <file>... DESTINATION <dir> [...])
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file(`SIZE`_ <filename> <out-var>)
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file(`READ_SYMLINK`_ <linkname> <out-var>)
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file(`CREATE_LINK`_ <original> <linkname> [...])
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`Path Conversion`_
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file(`RELATIVE_PATH`_ <out-var> <directory> <file>)
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file({`TO_CMAKE_PATH`_ | `TO_NATIVE_PATH`_} <path> <out-var>)
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`Transfer`_
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file(`DOWNLOAD`_ <url> <file> [...])
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file(`UPLOAD`_ <file> <url> [...])
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`Locking`_
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file(`LOCK`_ <path> [...])
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Reading
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^^^^^^^
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.. _READ:
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.. code-block:: cmake
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file(READ <filename> <variable>
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[OFFSET <offset>] [LIMIT <max-in>] [HEX])
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Read content from a file called ``<filename>`` and store it in a
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``<variable>``. Optionally start from the given ``<offset>`` and
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read at most ``<max-in>`` bytes. The ``HEX`` option causes data to
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be converted to a hexadecimal representation (useful for binary data).
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.. _STRINGS:
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.. code-block:: cmake
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file(STRINGS <filename> <variable> [<options>...])
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Parse a list of ASCII strings from ``<filename>`` and store it in
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``<variable>``. Binary data in the file are ignored. Carriage return
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(``\r``, CR) characters are ignored. The options are:
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``LENGTH_MAXIMUM <max-len>``
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Consider only strings of at most a given length.
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``LENGTH_MINIMUM <min-len>``
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Consider only strings of at least a given length.
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``LIMIT_COUNT <max-num>``
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Limit the number of distinct strings to be extracted.
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``LIMIT_INPUT <max-in>``
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Limit the number of input bytes to read from the file.
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``LIMIT_OUTPUT <max-out>``
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Limit the number of total bytes to store in the ``<variable>``.
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``NEWLINE_CONSUME``
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Treat newline characters (``\n``, LF) as part of string content
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instead of terminating at them.
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``NO_HEX_CONVERSION``
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Intel Hex and Motorola S-record files are automatically converted to
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binary while reading unless this option is given.
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``REGEX <regex>``
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Consider only strings that match the given regular expression.
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``ENCODING <encoding-type>``
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Consider strings of a given encoding. Currently supported encodings are:
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UTF-8, UTF-16LE, UTF-16BE, UTF-32LE, UTF-32BE. If the ENCODING option
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is not provided and the file has a Byte Order Mark, the ENCODING option
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will be defaulted to respect the Byte Order Mark.
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For example, the code
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.. code-block:: cmake
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file(STRINGS myfile.txt myfile)
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stores a list in the variable ``myfile`` in which each item is a line
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from the input file.
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.. _HASH:
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.. code-block:: cmake
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file(<HASH> <filename> <variable>)
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Compute a cryptographic hash of the content of ``<filename>`` and
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store it in a ``<variable>``. The supported ``<HASH>`` algorithm names
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are those listed by the :ref:`string(\<HASH\>) <Supported Hash Algorithms>`
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command.
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.. _TIMESTAMP:
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.. code-block:: cmake
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file(TIMESTAMP <filename> <variable> [<format>] [UTC])
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Compute a string representation of the modification time of ``<filename>``
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and store it in ``<variable>``. Should the command be unable to obtain a
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timestamp variable will be set to the empty string ("").
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See the :command:`string(TIMESTAMP)` command for documentation of
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the ``<format>`` and ``UTC`` options.
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Writing
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^^^^^^^
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.. _WRITE:
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.. _APPEND:
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.. code-block:: cmake
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file(WRITE <filename> <content>...)
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file(APPEND <filename> <content>...)
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Write ``<content>`` into a file called ``<filename>``. If the file does
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not exist, it will be created. If the file already exists, ``WRITE``
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mode will overwrite it and ``APPEND`` mode will append to the end.
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Any directories in the path specified by ``<filename>`` that do not
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exist will be created.
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If the file is a build input, use the :command:`configure_file` command
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to update the file only when its content changes.
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.. _TOUCH:
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.. _TOUCH_NOCREATE:
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.. code-block:: cmake
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file(TOUCH [<files>...])
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file(TOUCH_NOCREATE [<files>...])
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Create a file with no content if it does not yet exist. If the file already
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exists, its access and/or modification will be updated to the time when the
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function call is executed.
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Use TOUCH_NOCREATE to touch a file if it exists but not create it. If a file
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does not exist it will be silently ignored.
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With TOUCH and TOUCH_NOCREATE the contents of an existing file will not be
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modified.
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.. _GENERATE:
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.. code-block:: cmake
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file(GENERATE OUTPUT output-file
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<INPUT input-file|CONTENT content>
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[CONDITION expression])
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Generate an output file for each build configuration supported by the current
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:manual:`CMake Generator <cmake-generators(7)>`. Evaluate
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:manual:`generator expressions <cmake-generator-expressions(7)>`
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from the input content to produce the output content. The options are:
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``CONDITION <condition>``
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Generate the output file for a particular configuration only if
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the condition is true. The condition must be either ``0`` or ``1``
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after evaluating generator expressions.
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``CONTENT <content>``
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Use the content given explicitly as input.
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``INPUT <input-file>``
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Use the content from a given file as input.
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A relative path is treated with respect to the value of
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:variable:`CMAKE_CURRENT_SOURCE_DIR`. See policy :policy:`CMP0070`.
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``OUTPUT <output-file>``
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Specify the output file name to generate. Use generator expressions
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such as ``$<CONFIG>`` to specify a configuration-specific output file
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name. Multiple configurations may generate the same output file only
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if the generated content is identical. Otherwise, the ``<output-file>``
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must evaluate to an unique name for each configuration.
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A relative path (after evaluating generator expressions) is treated
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with respect to the value of :variable:`CMAKE_CURRENT_BINARY_DIR`.
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See policy :policy:`CMP0070`.
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Exactly one ``CONTENT`` or ``INPUT`` option must be given. A specific
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``OUTPUT`` file may be named by at most one invocation of ``file(GENERATE)``.
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Generated files are modified and their timestamp updated on subsequent cmake
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runs only if their content is changed.
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Note also that ``file(GENERATE)`` does not create the output file until the
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generation phase. The output file will not yet have been written when the
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``file(GENERATE)`` command returns, it is written only after processing all
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of a project's ``CMakeLists.txt`` files.
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Filesystem
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^^^^^^^^^^
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.. _GLOB:
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.. _GLOB_RECURSE:
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.. code-block:: cmake
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file(GLOB <variable>
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[LIST_DIRECTORIES true|false] [RELATIVE <path>] [CONFIGURE_DEPENDS]
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[<globbing-expressions>...])
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file(GLOB_RECURSE <variable> [FOLLOW_SYMLINKS]
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[LIST_DIRECTORIES true|false] [RELATIVE <path>] [CONFIGURE_DEPENDS]
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[<globbing-expressions>...])
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Generate a list of files that match the ``<globbing-expressions>`` and
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store it into the ``<variable>``. Globbing expressions are similar to
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regular expressions, but much simpler. If ``RELATIVE`` flag is
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specified, the results will be returned as relative paths to the given
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path. The results will be ordered lexicographically.
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If the ``CONFIGURE_DEPENDS`` flag is specified, CMake will add logic
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to the main build system check target to rerun the flagged ``GLOB`` commands
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at build time. If any of the outputs change, CMake will regenerate the build
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system.
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By default ``GLOB`` lists directories - directories are omitted in result if
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``LIST_DIRECTORIES`` is set to false.
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.. note::
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We do not recommend using GLOB to collect a list of source files from
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your source tree. If no CMakeLists.txt file changes when a source is
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added or removed then the generated build system cannot know when to
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ask CMake to regenerate.
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The ``CONFIGURE_DEPENDS`` flag may not work reliably on all generators, or if
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a new generator is added in the future that cannot support it, projects using
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it will be stuck. Even if ``CONFIGURE_DEPENDS`` works reliably, there is
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still a cost to perform the check on every rebuild.
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Examples of globbing expressions include::
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*.cxx - match all files with extension cxx
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*.vt? - match all files with extension vta,...,vtz
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f[3-5].txt - match files f3.txt, f4.txt, f5.txt
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The ``GLOB_RECURSE`` mode will traverse all the subdirectories of the
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matched directory and match the files. Subdirectories that are symlinks
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are only traversed if ``FOLLOW_SYMLINKS`` is given or policy
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:policy:`CMP0009` is not set to ``NEW``.
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By default ``GLOB_RECURSE`` omits directories from result list - setting
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``LIST_DIRECTORIES`` to true adds directories to result list.
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If ``FOLLOW_SYMLINKS`` is given or policy :policy:`CMP0009` is not set to
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``OLD`` then ``LIST_DIRECTORIES`` treats symlinks as directories.
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Examples of recursive globbing include::
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/dir/*.py - match all python files in /dir and subdirectories
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.. _RENAME:
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.. code-block:: cmake
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file(RENAME <oldname> <newname>)
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Move a file or directory within a filesystem from ``<oldname>`` to
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``<newname>``, replacing the destination atomically.
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.. _REMOVE:
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.. _REMOVE_RECURSE:
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.. code-block:: cmake
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file(REMOVE [<files>...])
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file(REMOVE_RECURSE [<files>...])
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Remove the given files. The ``REMOVE_RECURSE`` mode will remove the given
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files and directories, also non-empty directories. No error is emitted if a
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given file does not exist. Relative input paths are evaluated with respect
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to the current source directory. Empty input paths are ignored with a warning.
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.. _MAKE_DIRECTORY:
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.. code-block:: cmake
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file(MAKE_DIRECTORY [<directories>...])
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Create the given directories and their parents as needed.
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.. _COPY:
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.. _INSTALL:
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.. code-block:: cmake
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file(<COPY|INSTALL> <files>... DESTINATION <dir>
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[FILE_PERMISSIONS <permissions>...]
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[DIRECTORY_PERMISSIONS <permissions>...]
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[NO_SOURCE_PERMISSIONS] [USE_SOURCE_PERMISSIONS]
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[FOLLOW_SYMLINK_CHAIN]
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[FILES_MATCHING]
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[[PATTERN <pattern> | REGEX <regex>]
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[EXCLUDE] [PERMISSIONS <permissions>...]] [...])
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The ``COPY`` signature copies files, directories, and symlinks to a
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destination folder. Relative input paths are evaluated with respect
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to the current source directory, and a relative destination is
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evaluated with respect to the current build directory. Copying
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preserves input file timestamps, and optimizes out a file if it exists
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at the destination with the same timestamp. Copying preserves input
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permissions unless explicit permissions or ``NO_SOURCE_PERMISSIONS``
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are given (default is ``USE_SOURCE_PERMISSIONS``).
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If ``FOLLOW_SYMLINK_CHAIN`` is specified, ``COPY`` will recursively resolve
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the symlinks at the paths given until a real file is found, and install
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a corresponding symlink in the destination for each symlink encountered. For
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each symlink that is installed, the resolution is stripped of the directory,
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leaving only the filename, meaning that the new symlink points to a file in
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the same directory as the symlink. This feature is useful on some Unix systems,
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where libraries are installed as a chain of symlinks with version numbers, with
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less specific versions pointing to more specific versions.
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``FOLLOW_SYMLINK_CHAIN`` will install all of these symlinks and the library
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itself into the destination directory. For example, if you have the following
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directory structure:
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* ``/opt/foo/lib/libfoo.so.1.2.3``
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* ``/opt/foo/lib/libfoo.so.1.2 -> libfoo.so.1.2.3``
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* ``/opt/foo/lib/libfoo.so.1 -> libfoo.so.1.2``
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* ``/opt/foo/lib/libfoo.so -> libfoo.so.1``
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and you do:
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.. code-block:: cmake
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file(COPY /opt/foo/lib/libfoo.so DESTINATION lib FOLLOW_SYMLINK_CHAIN)
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This will install all of the symlinks and ``libfoo.so.1.2.3`` itself into
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``lib``.
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See the :command:`install(DIRECTORY)` command for documentation of
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permissions, ``FILES_MATCHING``, ``PATTERN``, ``REGEX``, and
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``EXCLUDE`` options. Copying directories preserves the structure
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of their content even if options are used to select a subset of
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files.
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The ``INSTALL`` signature differs slightly from ``COPY``: it prints
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status messages (subject to the :variable:`CMAKE_INSTALL_MESSAGE` variable),
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and ``NO_SOURCE_PERMISSIONS`` is default.
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Installation scripts generated by the :command:`install` command
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use this signature (with some undocumented options for internal use).
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.. _SIZE:
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.. code-block:: cmake
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file(SIZE <filename> <variable>)
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Determine the file size of the ``<filename>`` and put the result in
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``<variable>`` variable. Requires that ``<filename>`` is a valid path
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pointing to a file and is readable.
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.. _READ_SYMLINK:
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.. code-block:: cmake
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file(READ_SYMLINK <linkname> <variable>)
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This subcommand queries the symlink ``<linkname>`` and stores the path it
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points to in the result ``<variable>``. If ``<linkname>`` does not exist or
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is not a symlink, CMake issues a fatal error.
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Note that this command returns the raw symlink path and does not resolve
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a relative path. The following is an example of how to ensure that an
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absolute path is obtained:
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.. code-block:: cmake
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set(linkname "/path/to/foo.sym")
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file(READ_SYMLINK "${linkname}" result)
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if(NOT IS_ABSOLUTE "${result}")
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get_filename_component(dir "${linkname}" DIRECTORY)
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set(result "${dir}/${result}")
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endif()
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.. _CREATE_LINK:
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.. code-block:: cmake
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file(CREATE_LINK <original> <linkname>
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[RESULT <result>] [COPY_ON_ERROR] [SYMBOLIC])
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Create a link ``<linkname>`` that points to ``<original>``.
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It will be a hard link by default, but providing the ``SYMBOLIC`` option
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results in a symbolic link instead. Hard links require that ``original``
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exists and is a file, not a directory. If ``<linkname>`` already exists,
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it will be overwritten.
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The ``<result>`` variable, if specified, receives the status of the operation.
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It is set to ``0`` upon success or an error message otherwise. If ``RESULT``
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is not specified and the operation fails, a fatal error is emitted.
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Specifying ``COPY_ON_ERROR`` enables copying the file as a fallback if
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creating the link fails. It can be useful for handling situations such as
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``<original>`` and ``<linkname>`` being on different drives or mount points,
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which would make them unable to support a hard link.
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Path Conversion
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^^^^^^^^^^^^^^^
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.. _RELATIVE_PATH:
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.. code-block:: cmake
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file(RELATIVE_PATH <variable> <directory> <file>)
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Compute the relative path from a ``<directory>`` to a ``<file>`` and
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store it in the ``<variable>``.
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.. _TO_CMAKE_PATH:
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.. _TO_NATIVE_PATH:
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.. code-block:: cmake
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file(TO_CMAKE_PATH "<path>" <variable>)
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file(TO_NATIVE_PATH "<path>" <variable>)
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The ``TO_CMAKE_PATH`` mode converts a native ``<path>`` into a cmake-style
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path with forward-slashes (``/``). The input can be a single path or a
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system search path like ``$ENV{PATH}``. A search path will be converted
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to a cmake-style list separated by ``;`` characters.
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The ``TO_NATIVE_PATH`` mode converts a cmake-style ``<path>`` into a native
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path with platform-specific slashes (``\`` on Windows and ``/`` elsewhere).
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Always use double quotes around the ``<path>`` to be sure it is treated
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as a single argument to this command.
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Transfer
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^^^^^^^^
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.. _DOWNLOAD:
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.. _UPLOAD:
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.. code-block:: cmake
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file(DOWNLOAD <url> <file> [<options>...])
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file(UPLOAD <file> <url> [<options>...])
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The ``DOWNLOAD`` mode downloads the given ``<url>`` to a local ``<file>``.
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The ``UPLOAD`` mode uploads a local ``<file>`` to a given ``<url>``.
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Options to both ``DOWNLOAD`` and ``UPLOAD`` are:
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``INACTIVITY_TIMEOUT <seconds>``
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Terminate the operation after a period of inactivity.
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``LOG <variable>``
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Store a human-readable log of the operation in a variable.
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``SHOW_PROGRESS``
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Print progress information as status messages until the operation is
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complete.
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``STATUS <variable>``
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Store the resulting status of the operation in a variable.
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The status is a ``;`` separated list of length 2.
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The first element is the numeric return value for the operation,
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and the second element is a string value for the error.
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A ``0`` numeric error means no error in the operation.
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``TIMEOUT <seconds>``
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Terminate the operation after a given total time has elapsed.
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``USERPWD <username>:<password>``
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Set username and password for operation.
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``HTTPHEADER <HTTP-header>``
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HTTP header for operation. Suboption can be repeated several times.
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``NETRC <level>``
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Specify whether the .netrc file is to be used for operation. If this
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option is not specified, the value of the ``CMAKE_NETRC`` variable
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will be used instead.
|
|
Valid levels are:
|
|
|
|
``IGNORED``
|
|
The .netrc file is ignored.
|
|
This is the default.
|
|
``OPTIONAL``
|
|
The .netrc file is optional, and information in the URL is preferred.
|
|
The file will be scanned to find which ever information is not specified
|
|
in the URL.
|
|
``REQUIRED``
|
|
The .netrc file is required, and information in the URL is ignored.
|
|
|
|
``NETRC_FILE <file>``
|
|
Specify an alternative .netrc file to the one in your home directory,
|
|
if the ``NETRC`` level is ``OPTIONAL`` or ``REQUIRED``. If this option
|
|
is not specified, the value of the ``CMAKE_NETRC_FILE`` variable will
|
|
be used instead.
|
|
|
|
If neither ``NETRC`` option is given CMake will check variables
|
|
``CMAKE_NETRC`` and ``CMAKE_NETRC_FILE``, respectively.
|
|
|
|
Additional options to ``DOWNLOAD`` are:
|
|
|
|
``EXPECTED_HASH ALGO=<value>``
|
|
|
|
Verify that the downloaded content hash matches the expected value, where
|
|
``ALGO`` is one of the algorithms supported by ``file(<HASH>)``.
|
|
If it does not match, the operation fails with an error.
|
|
|
|
``EXPECTED_MD5 <value>``
|
|
Historical short-hand for ``EXPECTED_HASH MD5=<value>``.
|
|
|
|
``TLS_VERIFY <ON|OFF>``
|
|
Specify whether to verify the server certificate for ``https://`` URLs.
|
|
The default is to *not* verify.
|
|
|
|
``TLS_CAINFO <file>``
|
|
Specify a custom Certificate Authority file for ``https://`` URLs.
|
|
|
|
For ``https://`` URLs CMake must be built with OpenSSL support. ``TLS/SSL``
|
|
certificates are not checked by default. Set ``TLS_VERIFY`` to ``ON`` to
|
|
check certificates and/or use ``EXPECTED_HASH`` to verify downloaded content.
|
|
If neither ``TLS`` option is given CMake will check variables
|
|
``CMAKE_TLS_VERIFY`` and ``CMAKE_TLS_CAINFO``, respectively.
|
|
|
|
Locking
|
|
^^^^^^^
|
|
|
|
.. _LOCK:
|
|
|
|
.. code-block:: cmake
|
|
|
|
file(LOCK <path> [DIRECTORY] [RELEASE]
|
|
[GUARD <FUNCTION|FILE|PROCESS>]
|
|
[RESULT_VARIABLE <variable>]
|
|
[TIMEOUT <seconds>])
|
|
|
|
Lock a file specified by ``<path>`` if no ``DIRECTORY`` option present and file
|
|
``<path>/cmake.lock`` otherwise. File will be locked for scope defined by
|
|
``GUARD`` option (default value is ``PROCESS``). ``RELEASE`` option can be used
|
|
to unlock file explicitly. If option ``TIMEOUT`` is not specified CMake will
|
|
wait until lock succeed or until fatal error occurs. If ``TIMEOUT`` is set to
|
|
``0`` lock will be tried once and result will be reported immediately. If
|
|
``TIMEOUT`` is not ``0`` CMake will try to lock file for the period specified
|
|
by ``<seconds>`` value. Any errors will be interpreted as fatal if there is no
|
|
``RESULT_VARIABLE`` option. Otherwise result will be stored in ``<variable>``
|
|
and will be ``0`` on success or error message on failure.
|
|
|
|
Note that lock is advisory - there is no guarantee that other processes will
|
|
respect this lock, i.e. lock synchronize two or more CMake instances sharing
|
|
some modifiable resources. Similar logic applied to ``DIRECTORY`` option -
|
|
locking parent directory doesn't prevent other ``LOCK`` commands to lock any
|
|
child directory or file.
|
|
|
|
Trying to lock file twice is not allowed. Any intermediate directories and
|
|
file itself will be created if they not exist. ``GUARD`` and ``TIMEOUT``
|
|
options ignored on ``RELEASE`` operation.
|