msbuild: set a specific preprocessor #define in the command line

Question

In a C++ file, I have a code like this:

#if ACTIVATE
#   pragma message( \"Activated\" )
#else
#   pragma message( \"Not Activated\")
#endif

I

Answer 1

Use the CL environment variable to define preprocessor macros

Before calling MSBUILD, simply set the environment variable 'CL' with '/D' options like so:

set CL=/DACTIVATE to define ACTIVATE

You can use the '#' symbol to replace '=' sign

set CL=/DACTIVATE#1 will define ACTIVATE=1

Then make the call to MSBUILD

More documentation on the CL Environment Variables can be found at: https://msdn.microsoft.com/en-us/library/kezkeayy(v=vs.140).aspx