[CMake] Howto to work with variables from central makefiles....

[Eric Noulard]

2010/11/17 Thomas Lehmann <t.lehmann at rtsgroup.net>
>
> Hi all,
>
>
>
> for an automatically forced include I have provided an
>
> option like this:
>
>
>
> set(WIN32_SPEC ${CMAKE_CURRENT_SOURCE_DIR}/../../libs/global/win32_spec.h)

May you could use an absolute reference using

${PROJECT_SOURCE_DIR}/libs/global/win32_spec.h

if your project is name TOTO
(from the PROJECT(TOTO CXX) statement)
you use

${TOTO_SOURCE_DIR}/libs/global/win32_spec.h.

>
> add_definitions(-FI ${WIN32_SPEC})
>
>
> But when including this central file (find_package) the variable CMAKE_CURRENT_SOURCE_DIR
> changes and then the path and filename of the header is wrong.
>
>
>
> How to proceed best?
> Can I avoid that for those “set” statement the variable is not overwritten by those
> files including this central makefile?

You may use a CACHED variable
set(WIN32_SPEC ${PROJECT_SOURCE_DIR}/libs/global/win32_spec.h CACHE
FILEPATH "Central Include")

the first calling this will set the value then other set will be ignored.
If you want to override a CACHE var value you'll have to use FORCE set option.



--
Erk
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