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|
configure_file
--------------
.. only:: html
.. contents::
Copy a file to another location and modify its contents.
.. code-block:: cmake
configure_file(<input> <output>
[NO_SOURCE_PERMISSIONS | USE_SOURCE_PERMISSIONS |
FILE_PERMISSIONS <permissions>...]
[COPYONLY] [ESCAPE_QUOTES] [@ONLY]
[NEWLINE_STYLE [UNIX|DOS|WIN32|LF|CRLF] ])
Copies an ``<input>`` file to an ``<output>`` file while performing
`transformations`_ of the input file content.
If the input file is modified the build system will re-run CMake to
re-configure the file and generate the build system again.
The generated file is modified and its timestamp updated on subsequent
cmake runs only if its content is changed.
Options
^^^^^^^
The options are:
``<input>``
Path to the input file. A relative path is treated with respect to
the value of :variable:`CMAKE_CURRENT_SOURCE_DIR`. The input path
must be a file, not a directory.
``<output>``
Path to the output file or directory. A relative path is treated
with respect to the value of :variable:`CMAKE_CURRENT_BINARY_DIR`.
If the path names an existing directory the output file is placed
in that directory with the same file name as the input file.
If the path contains non-existent directories, they are created.
``NO_SOURCE_PERMISSIONS``
.. versionadded:: 3.19
Do not transfer the permissions of the input file to the output file.
The copied file permissions default to the standard 644 value
(-rw-r--r--).
``USE_SOURCE_PERMISSIONS``
.. versionadded:: 3.20
Transfer the permissions of the input file to the output file.
This is already the default behavior if none of the three permissions-related
keywords are given (``NO_SOURCE_PERMISSIONS``, ``USE_SOURCE_PERMISSIONS``
or ``FILE_PERMISSIONS``). The ``USE_SOURCE_PERMISSIONS`` keyword mostly
serves as a way of making the intended behavior clearer at the call site.
``FILE_PERMISSIONS <permissions>...``
.. versionadded:: 3.20
Ignore the input file's permissions and use the specified ``<permissions>``
for the output file instead.
``COPYONLY``
Copy the file without replacing any variable references or other
content. This option may not be used with ``NEWLINE_STYLE``.
``ESCAPE_QUOTES``
Escape any substituted quotes with backslashes (C-style).
``@ONLY``
Restrict variable replacement to references of the form ``@VAR@``.
This is useful for configuring scripts that use ``${VAR}`` syntax.
``NEWLINE_STYLE <style>``
Specify the newline style for the output file. Specify
``UNIX`` or ``LF`` for ``\n`` newlines, or specify
``DOS``, ``WIN32``, or ``CRLF`` for ``\r\n`` newlines.
This option may not be used with ``COPYONLY``.
Transformations
^^^^^^^^^^^^^^^
:ref:`Variables <CMake Language Variables>` referenced in the input
file content as ``@VAR@``, ``${VAR}``, ``$CACHE{VAR}``, and
:ref:`environment variables <CMake Language Environment Variables>`
referenced as ``$ENV{VAR}``, will each be replaced with the current value
of the variable, or the empty string if the variable is not defined.
Furthermore, input lines of the form
.. code-block:: c
#cmakedefine VAR ...
will be replaced with either
.. code-block:: c
#define VAR ...
or
.. code-block:: c
/* #undef VAR */
depending on whether ``VAR`` is set in CMake to any value not considered
a false constant by the :command:`if` command. The "..." content on the
line after the variable name, if any, is processed as above.
Unlike lines of the form ``#cmakedefine VAR ...``, in lines of the form
``#cmakedefine01 VAR``, ``VAR`` itself will expand to ``VAR 0`` or ``VAR 1``
rather than being assigned the value ``...``. Therefore, input lines of the form
.. code-block:: c
#cmakedefine01 VAR
will be replaced with either
.. code-block:: c
#define VAR 0
or
.. code-block:: c
#define VAR 1
Input lines of the form ``#cmakedefine01 VAR ...`` will expand
as ``#cmakedefine01 VAR ... 0`` or ``#cmakedefine01 VAR ... 1``,
which may lead to undefined behavior.
.. versionadded:: 3.10
The result lines (with the exception of the ``#undef`` comments) can be
indented using spaces and/or tabs between the ``#`` character
and the ``cmakedefine`` or ``cmakedefine01`` words. This whitespace
indentation will be preserved in the output lines:
.. code-block:: c
# cmakedefine VAR
# cmakedefine01 VAR
will be replaced, if ``VAR`` is defined, with
.. code-block:: c
# define VAR
# define VAR 1
Example
^^^^^^^
Consider a source tree containing a ``foo.h.in`` file:
.. code-block:: c
#cmakedefine FOO_ENABLE
#cmakedefine FOO_STRING "@FOO_STRING@"
An adjacent ``CMakeLists.txt`` may use ``configure_file`` to
configure the header:
.. code-block:: cmake
option(FOO_ENABLE "Enable Foo" ON)
if(FOO_ENABLE)
set(FOO_STRING "foo")
endif()
configure_file(foo.h.in foo.h @ONLY)
This creates a ``foo.h`` in the build directory corresponding to
this source directory. If the ``FOO_ENABLE`` option is on, the
configured file will contain:
.. code-block:: c
#define FOO_ENABLE
#define FOO_STRING "foo"
Otherwise it will contain:
.. code-block:: c
/* #undef FOO_ENABLE */
/* #undef FOO_STRING */
One may then use the :command:`target_include_directories` command to
specify the output directory as an include directory:
.. code-block:: cmake
target_include_directories(<target> [SYSTEM] <INTERFACE|PUBLIC|PRIVATE> "${CMAKE_CURRENT_BINARY_DIR}")
so that sources may include the header as ``#include <foo.h>``.
See Also
^^^^^^^^
* :command:`file(GENERATE)`
|
