That really only makes sense if you've got a 40 year old code base that supports every platform conceived, some of which have mouse origins that are -42.333f or

That really only makes sense if you've got a 40 year old code base that supports every platform conceived, some of which have mouse origins that are -42.333f or can only be determined at run time. Take a look at the source for tcsh, this is exactly how it is done there. Unless you're interested in supporting a long dead platform - it makes things unnecessarily complex. I love tcsh, but so many ifdefs in so many static functions...