Cygpath IF Error Handling

Question

How do you trap / test the return from cygpath in a script. That is, if you want to convert a windows directory but you don't know if it exists yet, you can't use -d on it (since you don't know if it exists and it's not in a windows format). However, if you cygpath a directory that doesn't exist, it errors and throws a message. Piping the results to > /dev/null doesn't help, since you still get the error message.