On 10/25/2011 12:09 AM, Daniel Dunbar wrote:
> Hi all,
>
> I've been searching for an answer to the following problem, with no luck:
>
> I have a CMake build that reads in some data from an external
> (non-CMake) file during configuration.
>
> I want to tell CMake that the configuration depends on this file, so
> that the --check-build-system / check_cache steps will know to
> automatically rebuild the project files / Makefiles / etc., whenever I
> edit the external file.
>
> Is this possible?
>
> Here is an example test case to demonstrate the problem, I want the
> project to know to rebuild when I change the version.txt file:
> --
> # Here is the test CMakeLists file that uses an external file:
> $ cat CMakeLists.txt
> cmake_minimum_required(VERSION 2.6)
>
> file(STRINGS "version.txt" VERSION)
> add_library(test t.cpp)
> add_definitions("-DVERSION=@VERSION@")
>
> # And here is the external file:
> $ cat version.txt
> 1
>
> # Do our first build.
> $ make
> [100%] Building CXX object CMakeFiles/test.dir/t.cpp.o
> Linking CXX static library libtest.a
> [100%] Built target test
>
> # Modify the external file.
> $ echo 2 > version.txt
>
> # Now we rerun make, but nothing is rebuilt because CMake
> # doesn't know the configuration depends on version.txt
> $ make
> [100%] Built target test
> --
>
> Thanks in advance,
> - Daniel
>From the top of my head, the easiest solution would be to do something
like this:
configure_file(version.txt ${PROJECT_BINARY_DIR}/version.txt COPYONLY)
Another possibility would be to create a CMake script (e.g. called
createVersionHeader.cmake) which reads version.txt and creates a header
file version.h defining VERSION which you then include everywhere where
it is required. In your CMakeLists.txt file you first configure_file
this script to contain the paths to PROJECT_SOURCE_DIR and
PROJECT_BINARY_DIR and you run it using add_custom_command. This has the
advantage that whenever version.txt changes, CMake doesn't have to
reconfigure the whole project, only an additional rule will be run.
HTH
Michael
--
Powered by www.kitware.com
Visit other Kitware open-source projects at
http://www.kitware.com/opensource/opensource.html
Please keep messages on-topic and check the CMake FAQ at:
http://www.cmake.org/Wiki/CMake_FAQ
Follow this link to subscribe/unsubscribe:
http://www.cmake.org/mailman/listinfo/cmake
