Measuring path length in bytes???

HI

Wonder if anyone has any clues on how I can measure the path length to a file and return that value in bytes?

I have some very heavily nested subfolders and this is hitting the Windows path size limit of some 264 bytes (can't remember that value exactly).
I want to run all the paths through a checker to check for this limit before further processing.

Any clues please?

cheers
malcom