How to build a program with 2 different values of a variable in CMake

Question

I've recently ported my Qt project from qmake to CMake. My main program contains a value which depends on a #define directive.

I want to specify that define directive externally via CMake and build 3 differently named versions of the same executable.

How should I do it?

I've seen set_target_properties but this only works for libraries and not for executables.

For example I want that the following program,

 int main()
 {

    cout << BUILDTYPE << endl;
 }

it's compiled in 3 different flavors (3 executables) based on the BUILDTYPE "define" For example in my CMakeLists.txt I want to specify

add_executable(myAppV1 -DBUILDTYPE=1)
add_executable(myAppV2 -DBUILDTYPE=2)
add_executable(myAppV3 -DBUILDTYPE=3)

but this is not the correct syntax. Some hint? and I get 3 executables which prints

Answer 1

Are you sure that set_target_properties does not work? How about this one:

set_target_properties(myAppV1 PROPERTIES COMPILE_FLAGS "-DBUILDTYPE=1")

or:

set_target_properties(myAppV1 PROPERTIES COMPILE_DEFINITIONS "BUILDTYPE=1")

On my machine it works:

add_executable(myAppV1 main.cpp)
add_executable(myAppV2 main.cpp)
set_target_properties(myAppV1 PROPERTIES COMPILE_DEFINITIONS "BUILDTYPE=1")
set_target_properties(myAppV2 PROPERTIES COMPILE_DEFINITIONS "BUILDTYPE=2")