[CMake] parsing config.h files and setting cmake variables accordingly

[Pau Garcia i Quiles]

Hello,

Take a look at CONFIGURE_FILE

On Fri, Feb 13, 2009 at 12:46 PM, Clemens Arth <clemens.arth at gmx.at> wrote:
> Hi,
>
> I've got a  question concerning  string processing in cmake. Our software
> framework consists of multiple libraries and has many different features to
> be enabled or disabled using #defines. For example, one option is to compile
> with OpenGL or with OpenGL ES support. Thus in a config.h file, one of two
> variables is valid to be #defined, USE_OPENGL or USE_OPENGLES. Depending on
> the variable defined cmake should link against a specific set of libraries.
>
> Currently determining which feature is set works the following way in my
> CMakeLists.txt:
>
> Code:
> # check for the configuration and set the corresponding GL/GLES libraries
> accordingly
> FILE(READ ${LIB_SOURCE_DIR}/include/config.h CURRENT_CONFIG)
> STRING(REGEX MATCH "\#define USE_OPENGLES" GLES_IS_SET ${CURRENT_CONFIG})
> STRING(REGEX MATCH "\#define USE_OPENGL" GL_IS_SET ${CURRENT_CONFIG})
> IF("#define USE_OPENGLES" STREQUAL "${GLES_IS_SET}")
>   MESSAGE("GLES config!")
> ELSE("#define USE_OPENGLES" STREQUAL "${GLES_IS_SET}")
>   IF("#define USE_OPENGL" STREQUAL "${GL_IS_SET}")
>       MESSAGE("GL config!")
>   ELSE("#define USE_OPENGL" STREQUAL "${GL_IS_SET}")
>       MESSAGE("Error! USE_GL or USE_GLES must be defined!")
>   ENDIF("#define USE_OPENGL" STREQUAL "${GL_IS_SET}")
> ENDIF("#define USE_OPENGLES" STREQUAL "${GLES_IS_SET}")
>
>
> Note that this is really a bad hack. First, if GLES_IS_SET is set ,GL_IS_SET
> is also set automatically. Second, if by accident the string does not
> exactly match the content (an additional <space>, or there is a second
> variable, for example called USE_OPENGL_EXTRAS), everything gets really
> weird or fails at all. Finally, a problem is that cmake does not actually
> notice if I changed the config.h file, so there should be an option to mark
> the configuration as dirty if the config.h file is altered - this is a
> problem which must not necessarily be solved, but maybe there is a simple
> solution to this.
>
> Can someone give me some tips how to improve my really ugly solution?
>
> Thanks and best regards
> Clemens
> _______________________________________________
> 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
>



-- 
Pau Garcia i Quiles
http://www.elpauer.org
(Due to my workload, I may need 10 days to answer)