Hi guys,
may I have a question about this idiom? Let's consider the next situation. Computer developer is writing an email to his supervisor where he's trying to explain why he didn't finish his project. His excuse is that he was exhausted...., and because developers are smart guys, he decided to use this idiom: "Sorry boss, I didn't have Oracle database for testing purposes, you didn't provide complete use case diagram and most of all, I was running on empty.". (this is that email) Now, please guys, how that boss will determine whether he was working although he had no energy left..(First definition of this idiom) or whether he just didn't know how to solve that project, after all that years. (second definition) ? Many thanks in advance for help guys, this idiom seems to be used really widely, so I want to learn it.

Best Regards
Doing all he can, with no energy (and possibly not much in resources). In the case of an automobile, it's used figuratively, because of course a car cannot run 'on empty' except for the visual of the fuel indcator resting 'on E'. [Another idiom, with cars, is to be riding 'on fumes'.]
Ok Philip, many thx for the explanation...Emotion: smile[Y]