How to define a C++ preprocessor macro through the command line with CMake?

Question

I try to set a preprocessor macro in the command line of CMake. I\'ve tried:

set generator=\"Visual Studio 8 2005\"
set params=-D MY_MACRO=1
cmake.exe -G %ge         


        

Answer 1

A good alternative would be to define a cmake option:

OPTION(DEFINE_MACRO "Option description" ON) # Enabled by default

Followed by a condition:

IF(DEFINE_MACRO)
    ADD_DEFINITIONS(-DMACRO)
ENDIF(DEFINE_MACRO)

Then you can turn that option ON/OFF via command line with cmake using the -D flag. Example:

cmake -DDEFINE_MACRO=OFF ..

To make sure the compiler is receiving the definition right, you can call make in verbose mode and check for the macro being defined or not:

make VERBOSE=1

This is a good solution also because make will recompile your code when any of cmake options changes.