Issue
I need to compile different versions of a certain project by adding compiler switches. Usually I would do this by using add_definitions or something like
set_property( TARGET mylib PROPERTY COMPILE_DEFINITIONS _MYDEFINE=1 )
in the CMakeLists.txt file.
In this specific project however, I am not allowed to modify any sources, including the CMakeLists.txt file.
I was hoping that something like
cmake -D_MYDEFINE=1 <path to sources>
would generate a project file (Visual Studio 2008 in my case, but shouldn't matter) which includes _MYDEFINE=1 in its preprocessor definitions but in fact it won't.
What are my options here? Is there a different cmake command line option to achieve this? Feel free to suggest solutions not including the command line, as long as changing the project's CMakeLists.txt is not necessary.
Solution
I managed to do it this way now:
I was able to convince everybody to add the following lines to the common CMakeLists.txt:
IF (NOT DEFINED _MYDEFINE)
SET(_MYDEFINE <default value>)
ENDIF()
ADD_DEFINITIONS(-D_MYDEFINE=${_MYDEFINE})
(No it is not really called "MYDEFINE", and <default value> is just a placeholder, I just replaced all that for this example)
This does not change the current behaviour of compiling with no additional compiler flags and is thus a valid change.
And it allows you to do
cmake -D_MYDEFINE=<my value> <path to sources>
where this cmake definition will be mapped to a C++ precompiler definition when cmake creates the project file.
Answered By - Tim Meyer Answer Checked By - Terry (WPSolving Volunteer)
