[CMake] Reading settings from generated files

[Eric NOULARD]

Le Mon, 12 May 2008 15:48:24 +0200,
Andrea Gualano <gualano at imavis.com> a écrit :

> I am cross-compiling for an embedded platform and I have to use a 
> third-party tool which, depending on a per-project configuration
> file, does the following:
> - compiles a .o file with some init code
> - generates a file containing a list of libraries to link against
> - generates a file containing some compiler flags
> 
> I am quite happy to do this with ADD_CUSTOM_COMMAND, since the
> operation is quite slow so I'd like to do that on make time, and also
> because the third-party tool is automatically rerun if the
> configuration file changes.
> 
> Now, the question is: how do I read the generated files to set things 
> like CMAKE_C_FLAGS and LINK_DIRECTORIES after the custom command is 
> executed?

I'm not sure to understand what you want?
* If you want to get the content of a generated file
  you may use FILE(READ ...)

> I could find no way to manipulate files after configuration time.

* if the problem is to read those file after they have been generated
  at make time then you may run a cmake script (which use FILE(READ )
  inside a ADD_CUSTOM_COMMAND which depends on the OUTPUT of the first
  one

something like:
  ADD_CUSTOM_COMMAND(...
                     COMMAND cmake -P yourCMakeScript.cmake
                     DEPENDS output_file.txt
                     ...)

this way you can execute any [scriptable] CMake command at build time.

however I do not know if _file_ (and not target) dependency works.
  
It would be easier if you give us excerpt of your CMakeLists.txt
at least the add_custom_command part including file name.

--
Erk